词汇讲解：
1. label vt.贴标签于；把…列为
例句：Make sure your luggage is properly labelled.
请务必把你行李上的标签贴好。
2. obscure adj. 费解的，难以理解的; 模糊不清的
例句：The point of his speech is obscure.
他发言的要点模糊不清。
3. promote vt. 推销
例句：He was in town to promote his new books.
他在城里推销他的新书。
4. tell vt. 识别;辨别
例句：I really can't tell which is which.
我实在看不出哪个是哪个。
5. contain vt. 包含; 容纳
例句：
