根据你所学内容，流感病毒应由的外壳和内部的组成。

阅读下面短文，选出最佳答案。

     What do we do when we go camping? First, we work out a plan. We take food, clothing, a knife, and

 things for cooking and eating. We take things to keep us away from insects and the sun.  

     Then we put everything into the car and we drive to the woods. We look for a place for campers and

  we look for a good place for our tent, the place should have a lot of moving air. This will keep some

 insects away.  High land with water on both sides of it is good.  Then we put up our tent.  We put

 everything into the tent, and we are ready for fun. We can swim in the lake, walk in the woods, climb a

 mountain, row a boat, or go fishing.

    In the evening we come back to the tent, we build a big fire because it can keep the insects away. We

 sit around the fire and talk, we may tell interesting stories or we may sing songs.

    At night we lie down on the grass.  We can look up at the stars. It is a busy day, so we try to go to

 sleep early.

    Everything is dark. Everything is quiet.  We hope we won't hear music from the radio in the next tent.

 We hope it won't rain.

1. Before going to camp we should first _____.

    A. draw up a plan              

    B. take some food

    C. take things to keep us warm    

    D. take something for cooking and eating

2. We go to camp _____.

    A. by bus    

    B. by car    

    C. by bike    

    D. on foot

3. Campers can take part in _____ activities.

    A. one or two    

    B. only a few    

    C. many    

    D. two or three

4. In the evening we build afire because _____.

    A. it is cold at night            

    B. it can keep us warm

    C. it can keep the insects away    

    D.  it is dark and quiet

5. The campers like to_____ at night.

    A. hear music from the radio  

    B. go to sleep early  

    C. have rain    

    D. be busy

如果代数式2x+1的值大于x+3的值，那么x的值为[ ]

A.x>2

B.x>-2

C.x<2

D.x<-2

具有如下转化关系的下列物质中，已知A、B、C、D都是氧化物，A、甲两种物质均为黑色粉末，乙为红色物质．请回答下列问题．

（1）写出两种黑色粉末的名称：A______，甲______；

（2）写出上述转化关系中，发生下列类型反应的化学方程式：化合反应______，分解反应______．

莱菔子不具有的药理作用是

A．助消化
B．缓解心绞痛
C．镇咳
D．祛痰
E．抗菌

水轮机尾水管的作用是（）

A.使水流在转轮室内形成涡流

B.引导水流进入导水机构

C.使转轮的水流排入河床，减少水头损失

D.排出水流