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问题 单项选择题

具有良好的抗水性能，可在－60~150℃的温度范围内使用，且化学稳定性好，非常适用于高速和精密的滚动轴承的润滑的润滑脂是（）润滑脂。

A、钙基

B、锂基

C、钾基

D、三硫化钼

答案

参考答案：B

阅读理解
阅读理解.根据材料内容,选择最佳选项
    Here are five points you can follow to improve your English, and the first point is the most important.
                                   It's your duty to achieve your aims (目标)!
    Studying English is your own duty and not the duty of your teacher or your parents. You must take an
active part in your clsses!
                                  Get a teacher or attend a class!
    It's a little difficult to study English alone. Also, it's difficult to learn how to speak English if you don't have an English teacher to talk with.
                                    Work as hard as possible in class!
    You need to practice speaking often. You should do all of your homework, reading and vocabulary
study outside class and then check the homework in class.
                                                 Keep studying!
    Don't stop for a long time such as during a summer holiday! To make good progress, you should study at least 5 hours each week.
                                        Make English your hobby and have fun!
    You can improve your English through other activities:
    Reading - choose English books that you can read.
    English songs - choose your favorite English songs and sing them again and again.
    DVDs - many films are also in English with subtitles in your language.
    Travel - traveling in English-speaking countries can help you with your English.
1. Point _____ is more important than any other point.
A. No. 1      
B. No. 2        
C. No. 4        
D. No. 5
2. According to the passage, an English learner should study _____ every week to make good progress.
A. about two hours  
B. at least four hours
C. at least five hours              
D. more than seven hours                      
3. The underlined word "subtitles" means "_____" in Chinese. 
A. 情节      
B. 字幕        
C. 画面        
D. 人物
4. Which of the following activities is NOT mentioned (提到)?
A. Reading English books.            
B. Singing English songs.
C. Watching English films.          
D. Writing e-mails in English.
5. The reading above is mainly about _____. 
A. how to improve your English        
B. why we need to learn English
C. how to study English for pleasure     
D. how we can sing English songs well
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单项选择题 A1/A2型题

下列说法不正确的是（）

A.老年恒牙的硬度要大于年轻恒牙

B.乳牙硬度小于恒牙

C.未萌牙的釉质密度低于恒牙

D.恒牙釉质密度大于乳牙

E.表面釉质的密度要低于釉牙本质界
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