15.
for different reasons 由于种种原因
for this/that reason 由于这个/那个原因
for no reason 没有任何理由
for some reason 由于某种原因

16.
take in 接受，吸收，理解
e.g. He read all kinds of books and take in as much useful information as possible.
He finds hard to take in the knowledge this way.
We need more time to take in the situation. 我们需要更多的时间研究目前的局势。
They listened to the lecture, but how much have they taken in, I wonder?
他们听了讲座，但我不知道他们听懂了多少。

17.
dynamic adj. 动力的,有活力的
e.g. a dynamic market. 有活力的市场
He is really a dynamic man. 他是个非常有活力的人。

18.
embed in adj. 使镶入，使嵌入
e.g. That terrible day will be embedded in the childrens memory. (喻)
那可怕的一天将深深印在孩子们的记忆中。
He suffered much from the bullet embedded in the bone.
嵌进骨中的子弹使他疼痛难忍。
These facts lie embedded in his mind.这些事实牢牢铭记在他的心中。

19.
the sense of touch 触觉
the sense of sight 视觉

20.
retrieve v. 重新得到，找回
e.g. retrieve a lost piece of luggage找回一件遗失的行李
retrieve ones spirits恢复精神
retrieve ones character/honor恢复名誉
retrieve an error /a loss补救错误/损失

21.
need
needn’t +have+过去分词：表示本来不必做而世纪已经做了的行为。相当于don’t need to do.
e.g. You needn’t have worried about her study.你不必担心她的学习。
You needn’t have done that by yourself.你本来不必自己做那件事情。
need doing sth=need to be done表被动。
e.g. The house needs painting. = The house needs to be painted.这房子需要粉刷。
The lock needs fixing. = The lock needs to be fixed. 这把锁需要修理。
另外，在want, require, worth 等词后接doing也表示被动意义。
e.g. The story is worth reading.这个故事值得一读。
The place is worth visiting.这个地方值得参观。

22.
crack the code 解码
the genetic code.遗传密码