重点讲解：
1. a number of 若干；许多；
例句：She retained a number of copies for further annotation.
她保留了许多副本以便作进一步的注解^BiU3b]BJU。
2. as usual 像平常一样；照例；
例句：Today, as usual, he was wearing a three-piece suit.
像往常一样，他今天穿的是三件套Ry3Ik9_[,Po。
3. by the way 顺便地；附带说一句；
例句：By the way, how did your seminar go?
对了，你的研讨会进行得怎样？
4. sth. happen to sb. （尤指不愉快的事）发生（在…身上）；(某人)遭到；遇到；
例句：If anything should happen to you, follow my advice.
万一你碰上什么意外，照我的话去做H[|TtJzhV,(WgHYD。