Ⅱ.重点句型详解

1．If burns are on arms or legs, keep them higher than the heart, if_possible. 如果烫伤的部位在臂部或腿部，如果可能的话就要把手臂或腿抬到高于心脏的位置。

if possible 为状语从句的省略，其完整形式为 if it is possible.

①If possible, do it by yourself.可能的话，你自己做。

②If possible, I‘ll go to Beijing tomorrow.如果可能的话，明天我要去北京。

拓展：if so 如果这样的话

if not 如果不是的话

if any 如果有的话

if necessary 如果必要的话

if ever 如果曾经有的话

[即境活用1]　—I hear Bob has been ill in hospital for days.

—______， let‘s go to see him.

A．If ever　　 B．If any  C．If possible D．If so

答案：D

解析：考查省略句 if so“如果这样的话”。

2．John was_studying in his room when he heard screaming. 约翰正在屋里学习，突然听到一声尖叫。

when 并列连词，意为“这时”，相当于 and then. when 作并列连词用时，构成并列句，意为“就在这时，恰恰在这时”，多用在下列句型中：

...be doing...when... 正在……这时……

...be about to do...when... 正打算做……这时……

be just going to do...when... 正要……这时……

had just done...when... 刚做了……这时……

be on the point of doing...when... 正要……这时……

①He was sleeping when there was a knock at the door.他正在睡觉，这时有人敲门。

②I was about to go out when someone knocked at the door. 我刚想出门，这时有人敲门。

③We had just begun to work when the machine broke down. 我们刚开始工作，这时机器坏了。

④The thief was on the point of putting his hand into the lady‘s handbag when the bus suddenly stopped.小偷正要把手伸进那位女士的手提袋中，这时公共汽车突然停了。

[即境活用2]　The children were playing football happily on the playground ______ it began to rain heavily.

A．as B．while C．when D．suddenly

答案：C

解析：句意为：孩子们正在操场上高兴地踢足球，这时天开始下起大雨。