1．(2019·全国Ⅰ) Modern methods ___63___ tracking polar bear populations have been employed only since the mid-1980s.

答案  for/of

考查介词用法。此处tracking polar bear populations作Modern methods的定语，用of连接，“methods of doing sth.”意为“……的方法”，构成固定结构；或者意为“对于跟踪北极熊的方法”用for。故填of/for。

2. (2018·全国Ⅲ) I was searching ________ these three western lowland gorillas I’d been observing.

答案　for

解析　search for寻找，为固定搭配。

3．(2017·全国Ⅰ) This trend，which was started by the medical community(医学界) ________ a method of fighting heart disease，has had some unintended side effects such as overweight and heart disease—the very thing the medical community was trying to fight.

答案　as

解析　此处指作为抵抗心脏病的一种方法。as表示“作为”，故填as。

4．(2017·全国Ⅲ) After school she plans to take a year off to model full-time before going to university to get a degree ________ engineering or architecture.

答案　in

解析　get a degree in在……方面获得学位，是固定搭配。

5．(2017·全国Ⅱ) It ran for just under seven kilometers and allowed people to avoid terrible crowds on the roads above as they travelled to and ________ work.

答案　from

解析　和and前的to对应，用from。to and from意为“来回”。

6．(2016·10月浙江) Drinking my iced coffee，I ran my fingers along the streets ________ the hotel to the opera hall.

答案　from

解析　这里指的是从宾馆的位置到歌剧厅的位置。from...to...为固定搭配，意为“从……到……”。故填from。

  In the chemistry lab，because 21.________ the student’s carelessness，the tube cracked and the liquid in it caused a fire on the table.Fortunately，he put it out 22.________ time at last.

  In fact，it is common to have some small accidents caused 23.________carelessness.I used to enjoy cooking，so I always sought a chance to cook.However，the desire led 24.________ an accident.

    Once I stayed 25._______home alone.I found it a chance to cook.I put all the food I needed 26.________ a pot.Then I had to wait 27.________ it to boil.In order to kill the waiting time，I went to watch TV.Only in a few minutes was I fascinated by a wonderful programme.It was about half an hour later that I remembered my food.I turned 28.________ the cooker immediately but unfortunately the food ran over 29.________ the pot.I was blamed and had to clean the kitchen.

    So we should pay attention 30.______ everything we are doing to avoid accidents.

21．答案　of

解析　设空处后的中心词为名词carelessness，设空处前为because，由此可判断设空处填of，because of是介词短语，意为“由于”。

22．答案　in

解析　句意为：幸运的是，最后他及时将火扑灭了。in time及时。

23．答案　by

解析　句意为：事实上，由于粗心而导致一些小事故很常见。by放在过去分词后，意为“被，由”。本句中caused by carelessness作定语，修饰accidents。

24．答案　to

解析　句意为：然而，这种做饭的欲望却导致了一次事故。lead to动词短语，意为“导致”。

25．答案　at

解析　句意为：一次我独自待在家里。stay at home为固定短语，意为“待在家里”。

26．答案　into

解析　句意为：我将我所需要的所有食物都放进一口锅里。put...into...将……放进……。

27．答案　for

解析　wait for固定短语，意为“等待”。

28．答案　off

解析　turn off关闭(煤气、电路等)。

29．答案　from

解析　run over from从……中溢出。

30．答案　to

解析　pay attention to为固定短语，意为“注意”。