好氧微生物需要氧气作何用？充氧效率与微生物生长有什么关系？

阅读理解。

     The earth has warmed by about half a degree (0.5) over the last 100 years. It could be getting warmer

on its own, but many scientists think that people are making the Earth warmer by making a greenhouse

effect (温室效应). The greenhouse effect is important. Without it, the Earth would not be warm enough

for us to live on. But just a little warmer than it is now could cause problems for humans, plants and animals.

     Many of things we do every day can change the Earth's temperature by sending greenhouse gases into

the air. We send greenhouse gases into the air when we watch TV, turn on lights, dry hair, play video games,

wash or dry our clothes or drive cars. The rubbish from factories and homes also produces greenhouse gases.

     Even a small change in temperature can affect our weather. This can cause changes in the sea levels,

the air, flooding, and our fresh water.

     The change in the temperature can also cause changes in the living places for animals and plants,

endangering many animals.

     Global warming (全球变暖) is a big problem, and every little bit we do can help. We can save electricity.

We can save energy in other ways such as by taking buses or walking rather than driving cars. We can

recycle to reduce the rubbish and save natural resources such as trees, oil and metals. We can buy products

that don't do bad to the environment and we can turn to solar energy. Remember the little bit that you do

will bring a better world.

1. _________ does not send greenhouse gases into the air?

A. Turning on a light

B. Walking to school

C. Driving a car

D. Watching TV

2. Without the greenhouse effect, we would _________.

A. not be able to live

B. be safer

C. have a cleaner earth

D. have a better world

3. The passage mainly talks about _________.

A. the earth could be getting warmer by itself

B. the earth is getting warmer in 100 years

C the greenhouse effect is important

D. humans are making the earth warmer

以学生选课关系SC(学号，课程号，成绩)为例，说明实体完整性规则的含义。

肺气肿患者，HRCT显示两肺上叶散在分布小圆形，无壁多发低密度区，大小约为2～10mm。属于哪种类型肺气肿()

A．全小叶型

B．小叶中心型

C．间隔旁型

D．瘢痕型

E．不规则型

动态投资回收期是指项目以( )抵偿全部投资所需的时间。

A．净现金
B．净收益
C．净现值
D．财务净现值

不良贷款依法清收的步骤包括了（）。

A.提起诉讼

B.财产保全

C.申请支付令

D.申请强制执行

E.申请债务人破产