近些年来形成了软件开发的多种模式，大致有三种类型：基于瀑布模型的结构化生命周期方法、

Some advice:

First: Always play in a safe place. A park is a safe place because there are no cars.

But don’t talk to anyone that you don’t know.

Second: Before you cross the road, stop and look both ways. Look left, look right, look left again.

Third: Don’t stay near dangerous buildings or houses. Something may fall on

your head.

Fourth: Medicines or pills（药丸）can be dangerous. Never swallow（吞下）any  bills or medicines you find in the cupboard.

Fifth: Wear a life jacket when you go out in a boat.

Sixth: Don't put your head out of a car , bus or train.

小题1:We are safe from cars_________.

A. if we play in the street              

B. if we play on the road

C. if we play in the park         

小题2:It’s __________ to take any pills you find in the cupboard.

A. safe              B. dangerous           C. allowed      

小题3:We_________ play games under a dangerous building.

A. should            B. shouldn’t            C. can

小题4:You have to _________when you go out by boat.

A .wear a life Jacket    B. eat much food       C wear a coat

小题5:We should________ before crossing the road.

A. look right           B. look left           C. look left ant right

下列不属于两栖动物的是（  ）

A．蟾蜍

B．大鲵

C．乌龟

D．蝾螈

I fell asleep while working on this paper_______the computer on.[ ]

A. as  

B. for  

C. over  

D. with

文言小说三个小说文体的基本要素。

所谓空气间隙的校验，即在（）情况下，绝缘子串风偏后导线对杆塔接地部分的空气间隙不得小于规定值。

A.外过电压

B.内过电压

C.最高运行电压

D.正常工作电压