重点讲解：
1. check out
查看；了解；
例句：I just want to drive around town and check out the main strip.
我就想驾车在城里兜兜，看看主要街市。
2. was/were supposed to do sth.
本应该(发生而没有发生)；
例句：Yes, but he was supposed to be back by now.
是的，可他该回来了。
3. lose track of
跟不上…的进展；不再掌握…的最新情况；
例句：It's so easy to lose track of who's playing who and when.
很容易就忘记谁要和谁比赛，什么时候比。
4. drop off
中途放下（某人）；中途卸下（某物）；
例句：Just drop me off at the airport.
就让我在机场下好了。
5. end up (in) sth./doing sth.
最终；结果；到头来；
例句：We talked so long,I end up missing class.
我们谈了好久，把课都给误了
