【词汇讲解】
1.Keep track of vt. 留意
如：Keep track of the time you actually travel.
把你旅行的实际时间记录下来。
Please ask if you cannot keep track of what I'm telling you.
如果你们听不懂我所讲的话，请提问。
2.strengthen v. 加强，变坚固
如：He has been brought in to strengthen the defence.
已请他来加强後卫力量。
The current strengthened as we moved down the river.
我们顺流而下时，水流更急了。
3.metabolism n. 新陈代谢
如：The dosage was geared down to a level which would work on the infected cells but not upset their normal metabolism.
药量已被减低到某一水平，既足以对付受感染的细胞，又不会干扰正常的新陈代谢。
4.bloated adj. 发胀的，浮肿的，傲慢的