下列物质中,两个氢原子的化学性质不同的是:() A.乙炔 B.甲酸 C.甲醛 D.乙

题型:单项选择题

问题:

下列物质中,两个氢原子的化学性质不同的是:()

A.乙炔

B.甲酸

C.甲醛

D.乙二酸

考点:水利水电工程第三章普通化学第三章普通化学题库
题型:单项选择题

阅读理解。

      Mr Wood is very old. He has seen many changes in his hometown.

      He knows that things are different now. But he never forgets the old days. He

likes to talk about them. He often talks about his favorite birds, the robins. "When I

was a boy, these houses were not here. There were wide fields and tall trees. Every

spring the robins would come. Thou sands of them would fly up to the north from the south. They spent the winter in the south. Some would build their nests(巢)in the trees near our houses. Then people started to cut down trees, and they built more houses. The robins stopped coming. They couldn't build their nests near our houses because

there were no trees. "

     "Now there are too many houses and too many roads. There are no places for the robins. They do not come any more. "

                            

1. Mr Wood often talks about          .

A. his old house        

B. the old days

C. his life now          

D. his family

2. The birds, the robins, spent the winter in        .

A. the south            

B. the west

C. the north            

D. the east

3. Then people _       trees because they wanted to build more houses.

A. cut down            

B. planted

C. bought              

D. watered

4. From the passage we can know that       .

A. Mr Wood likes his new life now

B. there were many houses there in the old days

C. the robins can make their nests without trees

D. Mr Wood is not happy with the changes there

题型:单项选择题

当a=3,b=1时,代数式0.5(a-2b)的值是(  )

A.1

B.0.5

C.0

D.2.5

题型:单项选择题

Um接口没有第2层的桢,且仅有一个字节的信令消息是Channel Request和()

A.Handover Request

B.Handover Access

C.Paging

D.Paging Res

题型:单项选择题

下列除哪项外,均是麝香的药理作用

A.抗炎

B.抗心肌缺血

C.调节中枢神经系统功能

D.抑制子宫平滑肌

E.抗血小板聚集

题型:单项选择题

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