a must

• 必备的知识或技能

a must的用法和样例：

例句

1. A raincoat is a must in the rainy season.
   在雨季雨衣是必备之物。
2. Our flat is such a long way from the office that a car is a must. There are no bus services at all!
   我们的住房离办公室有很长一段路，因而小汽车是必备的东西，那里根本没有公共汽车！
3. His new novel is a must for all lovers of crime fiction.
   他的新小说是罪案小说爱好者必须一读的。