重 点
If something is useful, you can use it to do something or to help you in some way. 有用的
adjective [原级] 有用的，有益的；<英，非正式>好的，熟练的
The pressure cooker is very useful for people who go out all day. 压力锅对整天外出的人非常有用。
- useful 出现在下面的课文中（提供视频、音频及笔记等可系统性学习）
- Lesson 58 A blessing in disguise?
- Lesson 59 Collecting
- Lesson 60 Too early and too late
- Lesson 1 Finding fossil man
- Lesson 17 A man-made disease
- Lesson 29 The hovercraft
