利用下列哪组数据,可以计算出地球的质量( ) ①已知地球半径R和地面重力加速度g

题型:选择题

问题:

利用下列哪组数据,可以计算出地球的质量(  )

①已知地球半径R和地面重力加速度g

②已知卫星绕地球做匀速圆周运动的轨道半径和r周期T

③已知月球绕地球做匀速圆周运动的周期T和月球质量m

④已知同步卫星离地面高h和地球自转周期T.

A.①②

B.①②④

C.①③④

D.②③④

考点:万有引力定律的其他应用
题型:选择题

在路口直行时,遇这种情形如何通行?

A、让左方道路车辆先行
B、让右方道路车辆先行
C、直接加速直行通过
D、开启危险报警闪光灯通行

题型:选择题
16是20的______%,20比______多
1
4
题型:选择题

阅读理解。

     In most languages, a greeting is usually followed by “small talk”. Small talk means the little things we

talk about at the start of a conversation. In English-speaking countries people often make small talk about

the weather: "Nice day, isn’t it?" "Terrible weather, isn’t it?" But there is something special about small talk. It must be about something which both people have the same opinion about. The purpose of small talk is to let both people agree on something. This makes meeting people easier and more comfortable. People

usually agree about the weather, so it is a safe topic for small talk. But people often disagree about religion or politics so these are not suitable topics for small talk in English. The topics for small talk also depend on where the conversation is taking place. At football matches, people make small talk about the game they

are watching: "Great game, isn’t it?" At bus-stops, people may comment about the transport system: "The bus service is terrible, isn’t it?"    

     Greetings and small talk are an important part of conversation in any language. The way people greet

each other and the things they talk about, however, may be different from one language to another. This

shows that there is much more to learn when we learn a language than just the vocabulary and the grammar of the language. We also have to learn the social behavior of the people who speak it.

1. Small talk is _____.

A. to let people disagree about something  

B. a kind of conversation with short words  

C. a greeting when people meet each other  

D. something we talk about to start with a conversation

2. The favorite topic of small talk is about _____.

A. games    

B. politics    

C. languages  

D. the weather

3. The passage suggests that when we learn a language _____.

A. we should know the culture about the country  

B. we should only master the grammar and vocabulary  

C. we should grasp the importance of the language  

D. we should learn about the transport system of the country

4. When we say “Great game, isn’t it?” we in fact _____.

A. have a conversation      

B. begin a small talk  

C. greet each other          

D. ask a question

5. What we learn from the passage is that _____.

A. in English-speaking countries we should talk about the weather  

B. different language has different grammar  

C. small talk is an important part in a language  

D. small talk depends on the purpose of the conversation

题型:选择题

下列在我国法院提起的诉讼中,构成涉外民事法律关系的有哪些?

A.发生在美国的犯罪行为因在我国发生结果而对犯罪嫌疑人追究刑事责任

B.中国公民和美国公民之间的婚姻关系

C.中国公民和德国公民之间的继承关系的

D.因发生在印度的交通事故而产生的侵权行为关系

题型:选择题

与叶刺是同源器官的有()。

A.鳞叶

B.捕虫叶

C.茎卷须

D.叶卷须

E.茎刺

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