下列说法不正确的是[ ] A.12C和14C互为同位素 B.乙醇与二甲醚(CH3

题型:选择题

问题:

下列说法不正确的是[ ]

A.12C和14C互为同位素                 

B.乙醇与二甲醚(CH3-O-CH3)互为同分异构体

C.红磷与白磷互为同素异形体            

D.H2O与D2O互为同位素

考点:同分异构体同位素同素异形体
题型:选择题

阅读理解.

     The dinosaurs once lived happily on the earth. But 65 million years ago, they suddenly died out. What

happened to them?

     Scientists think that a change in temperature may be to blame. They have come up with lots of ideas

to explain the end of the dinosaurs. 

     The most famous one is the minor planet (小行星) idea. Let's go back to that day 65 million years ago

to see what happened. Everything was OK before a large minor planet suddenly hit the earth. What a

terrible hit! It caused big fires, storms, acid rain (酸雨), and even earthquakes and volcano eruptions. The

hit produced a lot of dust, which flew up into the air and blocked the sun for months. The earth became

very cold without sunlight. The plants died first. Then the grass eating animals died of hunger. Then the

meat eating animals could not find food, either. They began to eat each other, but after a while they died

out, too. The dinosaurs, either plant-eaters or meat-eaters, did not live through the disaster. What a sad

story !

     In April, a British scientist thought of a new idea about the death of the dinosaurs.

     He thinks that after the minor planet hit the earth, the temperature change left more dinosaur

boys than girls! Without enough female dinosaurs to hatch the eggs, the dinosaur population became

smaller and smaller.

1.                  may be the main reason for the dinosaurs dying out according to scientists.

A. Big fires

B. Earthquakes

C. Acid rain

D. Temperature change

2. The passage mentioned                  ideas that the scientists came up with about the end of the dinosaurs.

A. two                        

B. three

C. four                        

D. five

3. The underlined expression "volcano eruptions" probably is                   .

A.the name of a minor plane

B. one kind of dinosaurs

C. one kind of disaster

D. the name of an earthquake

4. The earth became cold because                    .

A. the sun refused to rise

B. the dust kept the sunlight away

C. there's too much rain

D. there are too many dinosaurs

5. This passage may be found in                    .

A. a science fiction      

B. a story book

C. a dictionary          

D. a science magazine

题型:选择题

下列字符常量的写法中,错误的是( )。

A.'\105'

B.'*'

C.'\4f'

D.'\a'

题型:选择题

充填前牙楔状缺损的材料有多种,除外

A.复合体

B.银汞合金

C.流动树脂

D.玻璃离子粘固粉

E.光固化复合树脂

题型:选择题

根据银监会2007年印发的《商业银行内部控制指引》规定,内部控制的监督、评价部门应当独立于内部控制的建设、执行部门。

题型:选择题

在实现高效率城镇化的过程中,要坚持()的可持续发展方式。

A、循环节约

B、低碳生态

C、绿色环保

D、紧凑集约

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