Patterns
Whole sentences from infrastructure interviews, taken apart: the skeleton with its slots, what each chunk is doing grammatically, the expressions that carry the meaning, and ways to say the same thing. Highlights mark the parts worth memorising.
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System design6
Skeleton
Before I [动手做的事], let me make sure I understand [要确认的东西]: [问题一], [问题二], and [问题三]?
Structure
- Before I draw anything,时间状语从句,放在主句之前;draw 指在白板上画
用 anything 不用 something:还没画、带否定倾向的语境用 anything。
- let me make sure I understand the constraints祈使句 let me + 动词原形;make sure 后接宾语从句,that 省略
let me 是把主动权拿到自己手里但语气礼貌的标准句式;比 Can I ask a few questions 果断。
- how many users, which regions,冒号后是三个并列项,前两个是间接疑问短语,解释 constraints 是什么
间接疑问不倒装:是 how many users (we have),不是 how many users do we have;口语里把从句谓语省掉很自然。
- and what does 'down' cost us?第三个并列项,切成直接疑问语序,句末带问号
前两个是名词短语,第三个变成完整疑问句,是故意的:它最重要,语序变化让它突出。down 加引号表示「所谓的挂了」,暗示要先定义。
Key expressions
- let me make sure I understand让我先确认我理解对了
任何题开场都能用;后面接 the requirement / the question / what you are asking。
- what does X cost usX 对我们的代价是什么
cost 作及物动词带双宾语:cost us money / cost us a customer;问可用性预算时比 how important is uptime 具体。
- constraints约束
设计题第一个关键词。requirements 是要做到的,constraints 是不能越过的。
Variants
- Before I commit to anything, a couple of questions: X, Y?
- Can I check my assumptions first? I am assuming X and Y.
- What does a minute of downtime cost us, roughly?
System design#design#r12026-09-16
Skeleton
If I only had one [指标 / 预算 / 人] for [系统], it would be [你的选择].
Structure
- If I only had one SLO for this system,第二类条件句,if + 过去式表示假设
only 放在 had 前面,修饰整个动词短语;主句必须配 would。
- it would be主句,would + be
it 指代 that one SLO。
- the success ratio of signed-transaction broadcasts名词短语,of 结构;signed-transaction 是连字符复合形容词修饰 broadcasts
success ratio 是 SLI 的标准说法;broadcast 这里是名词,「广播出去的那笔交易」。
- at the gateway地点状语,指测量点
SLO 一定要说在哪一层测:at the gateway / at the load balancer / client-side。
Key expressions
- If I only had one X, it would be Y如果只能有一个 X,那就是 Y
强制排优先级的句式,任何「最重要的是什么」都能套。
- success ratio成功率
SLI 用 ratio 不用 rate;rate 是每秒多少。
- at the gateway在网关层测
SLO 落点分层的关键词。
Variants
- The one number I would put on a pager is X.
- If everything else were green and X were red, users would still be hurting.
System design#design#trust-wallet#r12026-09-16
Skeleton
Let me park [要挂起的话题] for now and circle back once [前置条件] is clear.
Structure
- Let me park caching for now祈使句;park 及物,宾语是话题名词;for now 是时间状语
park 是「暂时停放」的比喻,英语职场高频词;比 skip 好,因为它承诺了会回来。
- and circle back并列动词短语,主语仍是 me
circle back 是「绕回来」,偏美式职场口语;书面或英式可以用 come back to it。
- once the write path is clearonce 引导时间状语从句,「一旦…就」
once 比 when 多一层「条件满足之后」;从句用一般现在时表将来。clear 这里是「理清楚了」,不是「清空」。
Key expressions
- park X for nowX 先放一放
会议里也用:let's park that and take it offline。
- circle back (to X)回头再说 X
面试官会记得你说过要回来,所以真的要回来。
- once X is clear等 X 理清楚了
Variants
- I will come back to X once we have Y nailed down.
- Hold that thought on X; it depends on how we do Y.
- Let me set X aside for a second.
System design#design2026-09-16
Skeleton
I will start with [最简方案], and then point out [它在什么条件下会出问题].
Structure
- I will start with主谓 + 介词;将来时表示当下的打算
口语里缩成 I'll。不用 I would:这是你马上要做的事,不是假设。
- the simplest thing that meets the requirement最高级名词短语 + that 限定性定语从句
the simplest thing 后面必须跟限定,否则「最简单」没有边界;meets the requirement 就是那个边界。
- and then point out并列谓语,省略了重复的 I will
point out 是「指出」,比 explain 短,而且暗示你已经知道问题在哪。
- where it breaks as we scalewhere 引导的宾语从句,内嵌 as 状语
break 不及物,「失效、不再成立」;as we scale 的 as 是「随着」,不是「因为」。
Key expressions
- the simplest thing that works能用的最简方案
表明你不 over-engineer 的固定说法;后面可以直接接 which is a single region behind a load balancer。
- point out where it breaks指出它在哪会失效
break 在工程口语里泛指「不再成立」:the assumption breaks, the model breaks。
- as we scale随着规模上去
scale 不及物用法;要具体就说 at 10x the traffic。
Variants
- Let me start simple and add complexity only where the numbers force it.
- This works up to about X; past that, Y becomes the bottleneck.
- Version one is X. The first thing that breaks is Y.
System design#design#r12026-09-16
Skeleton
The trade-off is [你得到的好处] at the cost of [你付出的代价].
Structure
- The trade-off is主语 + 系动词,主系表结构的开头
trade-off 是可数名词,带 the 表示「这个方案里的那个取舍」;把它直接当主语,句子就是在下结论,不是在描述。
- lower latency表语,名词短语:比较级形容词 + 不可数名词
lower 是隐含比较,比较对象是「另一个方案」;不用说 lower than X,听的人知道。latency 不可数,前面不加 a。
- at the cost of介词短语,作后置状语,引出代价
固定搭配,of 后面接名词或动名词。比 but it makes X more complex 紧凑,而且把「这是代价」这个判断带出来了。
- a more complex failover storyof 的宾语,名词短语:冠词 + 比较级 + 复合名词
story 是工程口语,指「这一块的整体情况 / 方案」(the deployment story, the upgrade story),不是「故事」;比 failover mechanism 自然。
Key expressions
- at the cost of以…为代价
设计题里每个决定后面都能接;也可以放句首:At the cost of some latency, we get…
- failover story故障切换这一块
X story 在美式工程口语里很常见,表示「关于 X 的完整方案」;想书面一点就换成 failover path 或 failover design。
- lower latency更低的延迟
要给数字就说 latency drops from 200 to 80 milliseconds。
Variants
- X comes at the cost of Y.
- You get X, but you pay for it with Y.
- We are trading Y for X here.
- The price of X is Y.
System design#design2026-09-16
Skeleton
The trade-off here is [A] versus [B]. For [这个业务] I would pay [你选择承受的那个].
Structure
- The trade-off here is A versus B.主系表;here 是「在这个决定上」;表语是 A versus B 的对举结构
versus 口语里可以说 vs。两边要对称:都是不可数抽象名词。
- For a wallet介词短语作条件状语,置于句首
for + 业务类型 = 「对这种业务而言」;这是把通用取舍落到具体场景的转折点。
- I would pay the complexity.主谓宾;would 表示在这个假设场景下的选择
pay 直接接 the complexity 是比喻,把复杂度当成价格;the 指回前一句提到的那个 complexity。
Key expressions
- A versus BA 还是 B
列取舍两端的最短说法;比 between A and B 更有对立感。
- For a wallet, …对钱包这种业务来说
落地判断的万能开头:For a fintech / For an internal tool。
- I would pay X我愿意付 X 这个代价
表态用。和 at the cost of 是一对:那句陈述代价,这句选择代价。
Variants
- Given what an outage costs here, I would take the complexity.
- It is A versus B, and in this context A wins.
- I would rather carry A than risk B.
System design#design#trust-wallet2026-09-16
Incident2
Skeleton
In hindsight [当时的做法] was [问题所在]: it [实际情况], but what users felt was [用户感受].
Structure
- In hindsight介词短语作句首状语
固定搭配,不说 in the hindsight;等于 looking back。
- the alert was on the wrong signal主系表;on + signal 表示告警「打在」什么指标上
be on X 是监控口语:the alert is on error rate。
- it fired on CPU主谓 + on 状语
fire 是告警「触发」的标准动词;on CPU 省略了 CPU utilisation。
- but what users felt was latencywhat 引导的主语从句 + was + 表语
what users felt 是名词性从句作主语,谓语用单数 was;这个结构把「用户感受」推到句子前景。
Key expressions
- in hindsight事后看
复盘和 BQ 讲错误的开场词,承认判断有误但不自责。
- the alert fired on X告警因 X 触发
- what users felt was X用户感受到的是 X
symptom-based alerting 的一句话表达。
Variants
- Looking back, we were alerting on a cause, not a symptom.
- The signal we paged on was not the one users experienced.
Incident#incident#bq2026-09-16
Skeleton
We mitigated first by [止血动作], and only then [排查动作].
Structure
- We mitigated first主谓 + 副词 first
mitigate 在 SRE 口语里可以不及物(= 止血);first 放在动词后面强调顺序。
- by rolling backby + 动名词,表示手段
roll back 的动名词是 rolling back;rollback 连写是名词。
- and only then并列连词 + 强调副词短语
only then 是「直到那时才」。放在句中后面不倒装;放句首才要:Only then did we look for the root cause。
- went looking for the root causego + 现在分词,「去做某事」的口语结构
go looking for 有一点「出发去找」的画面感,比 investigated 生动;root cause 前用 the。
Key expressions
- mitigate first, then …先止血再…
故障叙述的骨架。面试官听到 mitigate 就知道你分得清止血和修复。
- only then直到那时才
强调顺序;句首用要倒装。
- go looking for着手去找
口语化的 investigate。
Variants
- Step one was stopping the bleeding; the root cause could wait.
- We restored service first and did the forensics afterwards.
- Rollback bought us the time to actually understand it.
Incident#incident#bq2026-09-16
Behavioral2
Skeleton
Off the top of my head it was [大概的数], but I would want to double-check [那个数 / 细节].
Structure
- Off the top of my head习语,介词短语作状语
字面是「从头顶上拿下来的」,即不查资料随口说;固定说法,head 用单数。
- it was around 40 percent主系表;around 表约数
around / about / roughly 都行;percent 美式写一个词,英式 per cent。
- but I would want to double-check转折 + would want to,弱化的意愿
I would want to 比 I want to 客气:「如果要给准数的话我会去查」。
- that number指示代词 + 名词,回指前面的 40 percent
用 that number 而不是 it,指代更清楚。
Key expressions
- off the top of my head凭印象
被问数字记不准时先说这句,再给数;比编一个精确数字可信。
- around / roughly / ballpark大约
三个都能用;ballpark 既是名词也是形容词:a ballpark figure。
- double-check再核实
带连字符的动词;比 verify 口语。
Variants
- I do not have the exact figure in front of me, but it was on the order of X.
- Roughly X; I can follow up with the exact number.
Behavioral#bq#incident2026-09-16
Skeleton
I pushed back on [方案 / 要求], and here is [你的替代方案].
Structure
- I pushed back on that主谓 + 介词 on + 宾语
push back on X 是「反对 X」的固定搭配,on 不能省;比 disagreed with 更有行动感。
- and here is并列句;here is + 名词,是倒装的呈现句
here is 用来「端出」东西,口语里很自然;后面单数用 is,复数 here are。
- the alternative I proposed instead名词 + 省略 that 的定语从句 + 副词
alternative 前用 the,特指你提的那一个;instead 放句尾,呼应前面被否掉的方案。
Key expressions
- push back on X反对 X
名词形式 pushback:there was some pushback from the team。
- here is what I proposed instead我提的替代方案是
BQ 里「说不」题的后半句;没有这半句只是抱怨。
- instead而不是那个
句尾一个词就把对比带出来。
Variants
- I did not think that was the right call, so I proposed X instead.
- My pushback was X; what I offered in its place was Y.
Behavioral#bq2026-09-16
AI & DevX1
Skeleton
That is where I would draw the line: [允许 AI 做的], but [必须由人做的].
Structure
- That is where I would draw the line主系表,where 引导表语从句;draw the line 是习语
draw the line 是「划界限」;would 表示这是你的立场,不是既成规则;冒号后面解释这条线画在哪。
- the agent can propose the Terraform change情态动词 can 表允许 + 及物动词 propose
propose 比 write 准确:它确实写出来了,但性质是「提议」。
- but a human runs the apply转折 + 一般现在时陈述规则
the apply 把 Terraform 的 apply 命令当名词用,工程口语;a human 用不定冠词,泛指「得是个人」。
Key expressions
- draw the line (at / between)划界限
AI 护栏、权限边界都能用:I would draw the line at production access。
- propose vs run提议 vs 执行
AI 边界的一对动词,一句话说清人机分工。
- a human in the loop人在回路
这句话的名词化说法。
Variants
- The agent gets read access and a plan; apply stays with a person.
- I am fine with AI writing it; I am not fine with AI shipping it unreviewed.
AI & DevX#ai#design2026-09-16
Closing1
Skeleton
Two things I would want to know before [某个决定]: [问题一], and [问题二]?
Structure
- Two things I would want to know名词短语 + 省略 that 的定语从句,作为独立的引导语
不是完整句,是冒号前「标题式」的开头;口语里很自然,书面要补 There are。
- before I say yesbefore 引导时间状语从句
say yes 直白但不失礼;比 accept the offer 轻松。
- what does on-call look like today直接疑问语序的问句,口语可接受
look like 问「大致情况」;today 指「现在」,不是「今天」。
- and what broke last quarter?第二个问句,过去式
break 的过去式 broke;last quarter 前面不加 in。
Key expressions
- what does X look likeX 大致是什么样
问情况的万能句:what does the deploy process look like。
- before I say yes在我答应之前
反问环节表明你在认真评估,不是单向被面。
- what broke出过什么故障
比 what incidents have you had 短,也更像内行。
Variants
- Two questions from my side: X, and Y?
- Before I decide, I would like to understand X.
Closing#bq#r22026-09-16