班主任评价的作用有()A．目标导向 B．反馈调节 C．监督促进 D．保证作用

药物的相互作用取决于：

A．药效学
B．药动学
C．二者均有
D．二者皆无

若3a ^2p-1 b ^2t-7与-4a ^4t+3 b ^8-p是同类项，则p=（    ），t=（    ）。

Mr. Fat is very rich. He has _____ money.[ ]

A. lots of

B. many

C. a little

Water is the most common substance(物质) found on the earth, but less than 1% of the earth’s water is suitable for drinking. More than 1,000,000,000 people around the world survive on just over 1 galon of water a day. Probebly more than 3,000,000,000 people may suffer from not having enough water by the year 2025. You are considered lucky if you live in a country where you can drink water out of your kitchen tap or bathroom tap. People in some countries have to pay for drinking water at home. So clean water is one of our most valuabe natural resources(资源).

In fact, peole waste so much clean water today. In factories lots of water is wasted. At home many people are not taking showers but still baths, and many are brushing their teeth with the tap turned on. Children are no longer taught how to save water….

You can save clean water in many ways. For example, if you keep gold fish, the tank water excellent for graden plants. And when you wash a milk bottle, pour the water on your house plants. Putting a brick or a water into your toilet tank many help use less water, saving many gallons over a long time.

Using rainwater is another simple way to save clean water. You can use rainwater to wash your hands after gardening, flush the toilet, and wash your car, your pet, your driveway when they are dirty.

For the same reason, people in Malaysia are encourageed to use rainwater. If one has a house with a small garden, he would buy a huge plastic tank to keep rainwater for their daily life.

小题1:We can learn from the passage ______.

A．when man can’t live without water

B．where there is no water resource

C．why there is less water on the earth

D．how important it is to save water小题2:According to the passage, one of the ways to save water is _______.

A．to stop keeping gold fish

B．to pay much for drinking water

C．to use it in a clever way

D．to educate those who waste water小题3:The underlined word “flush” in Paragraph 4 means “_______”.

A．clean something with water

B．pour water over something

C．make somehting wet with water

D．get water out of someghing小题4:People are ecouraged to use rainwater _______.

A．so that is can make our life easier

B．so that clean water can be kept for other uses

C．because is it free and easy to get

D．because there is no claen water left for them

已知A的阳离子有2个电子层，0.066 7 mol的A与足量的稀硫酸反应，放出2.24 L H₂（标准状况下）；B的最高价氧化物中含氧量为60%，气态氢化物中含氢量为5.88%，B原子核内质子数和中子数相等。通过计算回答A、B各是什么元素？