动手做Get your hands on it
练习跟着课文走 —— 每节课尾都有本课的练习。这一页是全部练习的总库，想集中刷题的时候来。 每个练习都写清了它来自哪一节，卡住了就回去看那一节。Practice follows the lessons — every lesson ends with the exercises for that lesson. This page is the whole library, for when you want to drill in one sitting. Each exercise names the lesson it came from, so you can go back when you stall.
练习Exercises
筛出 50 个练习（共 148 个） · 第 2 / 5 页。Showing 50 of 148 · page 2 / 5.假设要给 Notes Manager 加一个「显示当前有几条笔记」的文字。 这个数字应该怎么实现？
Say you have to add a line to Notes Manager that shows how many notes there are right now. How should that number be produced?
假设要加一个搜索框（在 NoteForm 上方，属于 NoteManager 的直接子元素）， 输入关键词后表格只显示匹配的笔记。 搜索关键词这个 state 该放在哪？
Say you add a search box above NoteForm, as a direct child of NoteManager. Once a keyword is typed, the table shows only the notes that match. Where should the state holding that keyword go?
README 只说了「不得修改任何 data-testid」。 下面哪些改动也会让现有测试失败？（多选）
The README says only that no data-testid may be changed. Which of the changes below also break the existing tests? (more than one)
这题是多选。More than one answer is correct.
下面哪个 handleDelete 能让四个测试全部通过， 但明显违反题目要求？
Which handleDelete below makes all four tests pass while clearly breaking what the task asks for?
你写的 handleSubmitNote 是 setNotes((prev) => [...prev, submittedNote])， 但自己加的测试报「找不到 My Title」。 测试代码是 userEvent.click(btn); expect(list).toHaveTextContent("My Title")。 最可能的原因？
Your handleSubmitNote is setNotes((prev) => [...prev, submittedNote]), but the test you added reports that My Title cannot be found. The test code is userEvent.click(btn); expect(list).toHaveTextContent("My Title"). What is the most likely reason?
假设签名改成 runTasks(promises: Promise<T>[], limit: number)， 调用方写 runTasks([task1(), task2(), task3()], 2)。 会发生什么？
Suppose the signature becomes runTasks(promises: Promise<T>[], limit: number) and the caller writes runTasks([task1(), task2(), task3()], 2). What happens?
有人写 return Promise.allSettled(tasks.map((t) => t()))。 它满足几条要求？
Someone writes return Promise.allSettled(tasks.map((t) => t())). How many of the requirements does it meet?
看真实 schema 里的 type Order。 下面哪些字段的类型是标量（不能再往下展开）？（多选）
Look at type Order in the real schema. Which of these fields have a scalar type — one that cannot be expanded any further? (Select all that apply.)
graphql-federation-practice/node-subgraph/src/schema.graphql这题是多选。More than one answer is correct.
真实 schema 里 createOrder 放在type Mutation 下。如果把它挪到type Query 下会怎样？
In the real schema, createOrder sits under type Mutation. What happens if you move it under type Query?
照 index.js 里 context 的真实结构， 哪个写法能拿到订单数据源？
Going by the real shape of context in index.js, which of these reads the order data source?
Order.shippingInfo 需要知道「是哪个 order 的物流」。 这个 order 的 id 从哪个参数拿？
Order.shippingInfo has to know which order the shipping belongs to. Which argument holds that order's id?