指针有哪些运算？请例举这些计算。

阅读理解。

     What is the sky? Where is it? How high is it? What lies above it? These questions are difficult to answer,

aren't they?

     Is the sky blue? The sky has no colour. We know that there is air around the world. When the planes fly,

they need air to lift their wings. Planes can not fly very high because when they go higher, the air gets thinner (薄的). If we go up about 1,200 kilometers from the earth. We find there is no air.

     Perhaps we can answer some of our questions now. The sky is space (太空). In the sky there is only the

son, the moon and all the stars.

1. What is the sky?

A. It's the clouds.

B. It's space.

C. It's air.

D. It's nothing.

2. The sky _______. 

A. is blue

B. is white

C. is black

D. has no colour

3. Planes can not fly very high because _______. 

A. the air becomes thinner.

B. the air becomes thicker.

C. the flying machine is not good.

D. the flying machine is bad.

4. If we go up about 1,200 kilometers from the earth, we find _______. 

A. there are more air

B. there is air

C. there is nothing but air

D. there is little air.

5. In space there is _______. 

A. nothing

B. air everywhere

C. anything

D. only the sun, the moon and all the stars.

2、2008年8月14日，中国国民党 * * 吴伯雄偕夫人来到祖籍地福建省永定县下洋镇思贤村，举行祭祖仪式并祭扫祖墓。 2000年11月，吴伯雄借赴龙岩参加世界客属恳亲大会之机首次返乡祭祖，时隔8年，他再次踏上了家乡的土地。这种尊宗敬祖的习俗源自于中国古代的（  ）

A.分封制  B 宗法制  C 世袭制 D 禅让制   

常用于中药粉针剂干燥的方法是

A．鼓式干燥

B．减压干燥

C．冷冻干燥

D．喷雾干燥

E．沸腾干燥

豆腐渣样 * * 分泌物主要见于（）

A.滴虫性 * * 炎

B.念珠菌性 * * 炎

C.子宫黏膜下肌瘤

D.老年性 * * 炎

E. * * 异物

乘坐旅客的车辆及停有该车辆的线路禁止溜放。