下列关于卤素的叙述，正确的是[ ] A．卤素是典型的非金属元素，因此不能与其他非

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                                                           The Real Chinese Food

     In China, there're many different kinds of food. Some of them are very popular. The real Chinese food is dumplings. Now let's talk about them, OK?

     Everyone in China likes dumplings very much, and there are many different kinds of dumplings. Some have meat and vegetables in them, others have sugar, eggs and so on. I like dumplings with vegetables and pork better than any other kind.

     Usually people make dumplings at home. If you have no time to make them, you can buy them from any supermarket. Then you take them home and eat them with vinegar.

     The Spring Festival is very important in China. When it comes, we make dumplings, usually we put a coin(硬币) in a dumpling. If one eats the dumpling with the coin in it, he or she will be lucky in the year.

     In the old days, people couldn't often eat dumplings, because they were very poor. Now our country is becoming stronger and stronger, and our people are richer and richer. We can eat them very often.

     Now tell me, do you like dumplings?

     Welcome to China, and we'll invite you to eat the real Chinese food -dumplings.

1. —What does the writer like dumplings with best? —        .

A. Meat.    

B. Seafood.    

C. Vegetables and pork.  

D. Vegetables.

2. You can buy dumplings from the supermarket when        .

A. you have time  

B. you are tired  

C. you are busy    

D. you are happy

3. The word "vinegar" in the passage means       .

A.糖      

B. 醋    

C.辣椒    

D. 酱油

4. Which of the following is NOT true ?

A. The Chinese like dumplings very much.

B. If someone eats the dumpling with the coin in it, he or she will be lucky in the year.

C. In the old days, people could only eat dumplings because they were poor.

D. Now people are rich and they often eat dumplings.

食管癌组织用Lugol溶液染色呈（）

A.棕色

B.黄色

C.红色

D.绿色

E.粉色

如图6—4—21所示，有一倾角为30°的光滑斜面，斜面长L为10m，一小球从斜面顶端以10m/s的速度沿水平方向抛出，求：（1）小球沿斜面滑到底端时水平位移s；（2）小球到达斜面底端时的速度大小。（g取10 m/s²）

“光电互补型”太阳能热水器，晴天以吸收太阳能作为加热方式，阴雨天可用电加热方式．

（1）某太阳能热水器的水箱内盛有120 kg的水，当水温由15℃升高到45℃时．这些水吸收的热量是多少？已知水的比热容c_水=4.2×10³J/（kg•℃）

（2）若该热水器采用电加热方式工作时的效率为70%，则要使120kg的水由15℃升高到45℃消耗的电能是多少千瓦时（kW•h）？

随时抽查原料质量，混凝土配合比经监理工程师审批确认，评定混凝土强度，按月向监理报送评定结果，这是针对可能发生的（）质量问题而采取的预控措施。

A.混凝土强度不足

B.斜孔、断桩

C.钢筋笼上浮

D.缩颈、堵管