大气垂直递减率的含意是（ ）。 A．气温随高度上升气温下降的现象 B．气温随高度上升

腹痛病因病机与下列哪项无关（）。

A.外感时邪

B.饮食不节

C.情志失调

D.阳气素虚

E.高年体虚

群体规范会形成群体压力，在压力下成员有可能放弃自己的意见而采取与大多数人一致的行为，即（）。

阅读理解。

     Scientists are trying to make the deserts into good land again. They want to bring water to the deserts, so

people can live and grow food. They are learning a lot about the deserts. But more and more of the earth is

becoming desert all the time. Scientists may not be able to change the desert in time.

     Why is more and more land becoming desert? Scientists think that people make deserts. People are doing

bad things to the earth.

     Some places on the earth don't get much rain. But they still don't become deserts. This is because some

green plants are growing there. Small green plants and grass are very important to dry places. Plants don't let

the sun make the earth even drier. Plants do not let the wind blow the dirt away. When a bit of rain falls, the

plants hold the water. Without plants, the land can become desert more easily.

1. Deserts _____. [ ]

A. never have any plants or animals in them

B. can all be turned into good land before long

C. are becoming smaller and smaller

D. get very little rain

2. Small green plants are very important to dry places because _____. [ ]

A. they don't let the sun make the earth even drier

B. they don't let the wind blow the soil away

C. they hold water

D. All of the above

3. Land is becoming desert little by little because _____. [ ]

A. plants can't grow there

B. there is not enough rain

C. people haven't done what scientists wish them to do

D. scientists know little about the deserts

4. After reading this passage, we learn that _____. [ ]

A. plants can keep dry land from becoming desert

B. it is good to get rid of the grass in the deserts

C. all places without much rain will become deserts

D. it is better to grow crops on dry land than to cut them

请讲述汉氏氧气分析仪的开机步骤

推力瓦的俯视为何形状？为何用钨金作瓦面？