A recent study showed how the temperature. water freezes.can be changed using electric charges．( )A．at whichB．for whichC．in whichD．with which 题目和参考答案——青夏教育精英家教网——

题目内容

18．A recent study showed how the temperature，______ water freezes，can be changed using electric charges．（　　）

A．

at which

B．

for which

C．

in which

D．

with which

分析最近的一项研究展示了水的结冰温度是如何通过电荷来改变．

解答答案：A
题干中water freezes是修饰temperature的一个非限制性定语从句；从句中freeze与先行词temperature之间要添加介词at，即freeze at the temperature．故选A．

点评定语从句是用来修饰名词的形容词性从句，相当于一个形容词．连接定语从句的引导词分为关系代词和关系副词，关系代词在从句中要作主语或宾语；关系副词在从句中作状语．这也是选择关系词的一个判断方法．

练习册系列答案

小学升初中核心试卷系列答案

小学升初中进重点校必练密题系列答案

期末测试卷系列答案

小学培优总复习系列答案

小学科学探究手册系列答案

小学达标训练系列答案

小学毕业综合复习系列答案

小学毕业特训卷系列答案

小学毕业升学总复习系列答案

小学毕业升学模拟试卷系列答案

相关题目

4．It's ten years since the scientist _______on his life's work of discovering the valuable chemical．（　　）

9．What do astronauts eat in space，and why？How did astronaut food come into being？How do astronauts preserve food for long periods of time in space？NASA（the National Aeronautics and Space Administration）（美国国家航空航天局）has been researching food for space travel since the 1960's to find the best way of keeping astronauts from going hungry．
    The research could date from an accident that took place on the first manned Gemini mission in 1965．astronaut John Young managed to sneak（偷偷地拿）a corned beef sandwich onto the GeminniⅢcapsule to eat during its orbit around Earth．To Young's surprise，the sandwich plan did not go as expected； instead the sandwich began to break apart and scatter（散开）through the GeminniⅢcapsule．This could have resulted in disaster，since a small piece of food could have stuck in the air vents（通风孔）and other equipment．The sandwich was stuffed into a pocket to avoid the further mess insid e the small space capsule This incident caused NASA to enforce strict rules on what types of food can be taken into space．
    Space food has come a long way since then．During the Gemini period，the astronauts mostly ate cubed，compr essed foods（压缩食品）high in calories and lightweight．
    NASA expects a long shelf life for space food．The majority of food taken into space has been dried out or heat-treated．These process and use of sodium（钠），make the food taken into space last longer．Research is ongoing into space food to seek out healthier ways to preserve it．Too much sodium is unhealthy，and can badly change the taste of some foods．

39．What happened to John Young in the G eminniⅢcapsule？B
A．His sandwich went bad as expected
B．He couldn't eat the sandwich he had bought
C．His sandwich caused trouble to some equipment
D．He filled his pocket with the sandwich．
40．Why has NASA set up strict rules on the space since the 1960's？A
A．To protect the astronauts'safety
B．To provide enough food for astronauts
C．To limit how much junk food astronauts eat
D．To make it easy for astronauts to get enough nutrition
41．The majority of the space food is dried out or heat-treated in order toD．
A．keep astronauts healthy
B．keep it from breaking apart
C．change its taste
D．make it last longer
42．What is the text mainly about？B
A．How to make space food
B．The history of space food
C．A food incident in the Gemini capsule
D．The process of making space food．

6．It is very different from the．situation in the wild，the vast majority of camels will die or be killed before they grow up．（　　）

13．-It's too late．I must leave now．
-I can't allow you to go home in this weather．（　　）

3．，the house isn't attractive enough，thought the price itself is quite reasonable．（　　）

	A．	On the contrary		B．	Generally speaking
	C．	In particular		D．	To be honest

10．There is little chance that we will manage to change the law． ____，it is important that we try．（　　）

7．Are morning people born or made？In my case it was definitely made．In my early 20s，I rarely went to bed before midnight，and I would almost always get up late the next morning．
But after a while I couldn't ignore the high relationship between success and rising early．On those rare occasions where I did get up early，I noticed that my productivity was almost always higher．So I set out to become a habitual early riser．But whenever my alarm went off，my first thought was always to stop that noise and go back to sleep．Eventually some sleep research showed me that I was using the wrong strategy．
The most common wrong strategy is this：You assume that if you're going to get up earlier，you'd better go to bed earlier．It sounds very reasonable，but will usually fail．
There are two main schools（流派） of thought on sleep patterns．The first is that you should go to bed and get up at the same time every day．The second school says you should go to bed when you're tired and get up when you naturally wake up．However，I have found both of them are wrong if you care about productivity．If you sleep at set hours，you'll sometimes go to bed when you aren't sleepy enough．You're wasting time lying in bed awake and not being asleep．
If your sleep is based on what your body tells you，you'll probably be sleeping more than you need．Also，your mornings may be less predictable if you're getting up at different times．
The solution for me has been to combine both methods．I go to bed when I'm sleepy and get up with an alarm clock at a fixed time．So I always get up at the same time （in my case 5am），but I go to bed at different times every night-sometimes at 9：30pm，and other times at midnight．Most of the time I go to bed between 10-11pm．
However，going to bed only when I'm sleepy，and getting up at a fixed time every morning is my way．If you want to become an early riser，you can try your own．

59．According to the passage，the underlined phrase refers toC．
A．people who stay up until the next morning
B．people who feel sleepy in the morning
C．people who get up early in the morning
D．people whose productivity is the highest in the morning
60．Why did the author want to become a habitual early riser？C
A．Because he/she wanted to form the habit of going to bed early and getting up early．
B．Because he/she wanted to see which of the two main schools of thought on sleep patterns was right．
C．Because he/she had found that his/her productivity was higher when he/she got up early．
D．Because he/she was told the high relationship between success and rising early．
61．The author experienced all the following EXCEPTA．
A．asking scholars for advice on sleeping habits
B．getting up early occasionally
C．pressing off the alarm to go on sleeping
D．going to bed after midnight
62．The passage is mainly aboutB．
A．how to have good sleep
B．how to become an early riser
C．wrong strategies for getting up early
D．main schools of thought on sleep patterns．

8．-See the gathering clouds outside？Please take this umbrella with you．
- ．（　　）

	A．	Thanks．Take it easy		B．	OK，just in case
	C．	Well，it just depends		D．	All right．I'll try my luck