石油矿藏分为哪几种类型，它们是怎么划分的？

Hong Kong has about forty public beaches. Some of them are very famous around the world. People can go there for a swim. You can go to them by bus. To go to some beaches yu must take a boat.

You will swim there without danger if you remember these instructions:

?Never swim alone.

?Never go out in a boat if you cannot swim.

?Never swim after a meal or when you feel hungry or tired.

?Don’t stay in the water too long.

Remember:A red flag means that it is dangerous for anybody to go into the water.A blue flag means that it is dangerous for children.

根据短文内容，判断下列各句正误。正确的在题前括号内写“T”，错误的写“F”。

小题1:There are about 40 public beaches in Hong Kong.

小题2:You should swim after a meal.

小题3:You can take a bus to go to most of the public beaches.

小题4:You’d better swim when you’re alone.

小题5:If you were a child, you could swim when you saw a red flag.

关于质量守恒定律，下列叙述中正确的是（　　）

A．煤燃烧化为灰烬，该反应不符合质量守恒定律

B．24克镁在空气中完全燃烧生成40克氧化镁，实际消耗空气质量为16克

C．一切化学反应都遵从质量守恒定律

D．质量守恒定律只适用于有气体或固体生成的化学反应

经营活动的现金净流量反应了企业对外投资的收益获取能力。

珍视明滴眼液是国家中药保护品种，是经国家教委评审通过推荐的青少年“防近视”产品。

错构症