第一次看此系列文的朋友，請先移步到 Day 1 – 如何開始？進行方式、自我介紹實戰 哦！

🎬 情境故事

面試官：「讓你來設計一個演唱會的搶票系統，你會如何設計？」
我知道在設計前要釐清需求，但是該如何用英文開始呢...?

👉 今日目標：先能有一個「拆解架構的口語框架」，不用馬上講得完美。

🤖 Config Prompt

[Config]
- Day: Day4 – System Design (Ticket Booking System)
- Scenario: Job interview — designing a scalable ticket booking system (e.g., for concerts or trains).

👉 在練習之前...

以設計搶票系統為前提，想一下：

1. 如何釐清需求（需要先問什麼問題？）
2. 核心限制是什麼（高流量、超賣、交易一致性）
3. 系統該有哪些元件（前端、API Gateway、DB、快取）
4. 有哪些可能的挑戰（高併發）

並且把關鍵字寫下來。

我的關鍵字：

1. essential features, response time, peak loading
2. to avoid race condition, transactional consistency
3. database, cache, queue
4. high throughput, dead lock

🎯 開始進行練習

記得把對話錄下來，自己聽一次，想想有哪裡不自然。

📌 小技巧

如果 GPT 還沒完整對話完就想要結束對話，可以請他繼續。

We can keep going.

I don't finish. Let's keep going.

🆘 今日救命句

• 救命句（簡短切入專案）：

  Let me clarify step by step.

• 爭取思考時間：

  That’s an important point. Let me organize my thoughts.

🔑 核心句型

1. 釐清需求 (Clarify requirements)

   • First, I need to confirm the ticketing rules, such as seat limits and payment flow.
   • Let me check if the system must handle both web and mobile traffic.

2. 拆解系統 (Break into components)

   • I would separate the system into frontend, backend services, and database.
   • The booking flow needs services for authentication, payment, and seat allocation.

3. 處理挑戰 (Address challenges)

   • The key challenge is overselling, so we need strong concurrency control.
   • To handle peak traffic, I would use caching, load balancing, and queueing.

4. 做取捨 (Explain trade-offs)

   • This design increases consistency, but may reduce performance.
   • Using queues helps scalability, but adds delay in confirmation.

📝 我的今日反饋

今天感覺我進步很多！在說話時我說的比以前慢，花更多時間在思考之前常常犯的錯。例如：is/are, for/to/on, 複數的 s 結尾。

今天在聽 feedback 的時候，也花更多心力在聽這些聲音比較小的詞。Repeat 的時候也更注意在這些詞上面。

尤其是今天說到 any information about peak loading?, GPT 糾正我要說 any information on peak loading。
我覺得很酷，根本不知道可以這樣說。

Per-turn Corrections:
	•	“You mean: I’ve been working as a backend engineer for three years.” (alternative: “I’ve been a backend engineer for about three years.”)
	•	“You mean: What are the essential features?” (alternative: “What kind of core features are needed?”)
	•	“You mean: The system should consume the queue concurrently.” (alternative: “We should process the queue with multiple workers at the same time.”)

Top 3 Patterns:
	1.	Clarifying Questions: Great job asking for requirements; just keep it simple.
	2.	Using “like” as a filler: Try to reduce it a bit.
	3.	Rephrasing for Precision: Good effort in rephrasing your thoughts.

Phrase Pack:
	•	“Let’s handle a lot of users at once.”
	•	“We need strong concurrency control.”
	•	“What are the key requirements for response time?”
	•	“We’ll design the system around a queue.”
	•	“We should process requests concurrently to keep it fast.”

Intonation Tip:
Try to emphasize the key noun when you ask for details. For example: “What are the essential features?” to highlight what you’re focusing on.

Fluency & Pronunciation Notes:
	•	Overall clear and steady.
	•	Just slow down a bit on longer sentences.
	•	Great job repeating corrected phrases.

Key Focus for Next Time:
	1.	Practice asking about requirements confidently.
	2.	Work on cutting down filler words like “like.”
	3.	Do a 2-3 minute drill on summarizing system design steps.
```Day 4 – 系統設計