描写人物有哪些方法？

根据短文判断下列句子的正确(T) 与错误(F)。

     Your home is a safe place, right? Think again. 

     Many serious accidents happen in people's homes. 

     Could you please prevent these accidents? Yes. Many accidents happen because people are careless.

So be careful! Here are some tips about safety. 

     Don't stand on chairs. Many people may fall off chairs and hurt themselves. 

     ●Keep the floor dry, and you won't slip (滑) or fall. 

     ●Be away from matches. Even a cigarette (香烟) can easily start a fire. Don't use water to put out fires.

Use salt instead. 

     ●Be careful with knives! Many people cut them- selves in the kitchen. Never touch the broken bottles,

doors or windows. Glass can also cause the most senous cuts. 

     ●Don't keep poisons (毒药) in the kitchen. 

     ●Never use electrical appliances (电器设备) in the shower. Dry the floor before you use them, or electricity

can hurt you! 

     ●Keep children away from hot water and hot drinks. They can be dangerous. But adults often forget it. 

     ●Look through the peephole (门镜) when you hear the knock on the door. Don't let strangers in.

     In a word, we should learn to protect ourselves and stay away from danger.

( )1. You must be careful when there is water on the floor.

( )2. Salt can't be used for putting out fires.

( )3. It's not safe for people to touch switches (电源插座) with wet hands.

( )4. Water and drinks can be dangerous for both children and adults.

( )5. Open the door at once when you hear someone knocking at the door.

Our supply of food is ________ now . We’d better store some .

A．running out

B．running out of

C．run out

D．using up

若关系R、S如下图所示，π_1,3,7(σ_3＜6(R×S))= (30) ，且结果集的元组列数和元组个数分别为 (31) ，R÷S= (32) 。

（31）处填（）。

A．4和8

B．3和8

C．3和5

D．7和5

氯化钠是一种重要的化工原料。电解氯化钠溶液可制得氢氧化钠等物质，反应的化学方

程式为2NaCl + 2H₂O   ^通电 X↑+ H₂↑+ 2NaOH。则X的化学式为

A．Cl₂

B．HCl

C．HClO

D．HClO₃

抢救巴比妥类中毒所致呼吸衰竭的重要措施是什么？