Ⅱ.重點句型詳解

1．If burns are on arms or legs, keep them higher than the heart, if_possible. 如果燙傷的部位在臂部或腿部，如果可能的話就要把手臂或腿抬到高于心臟的位置。

if possible 為狀語從句的省略，其完整形式為 if it is possible.

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

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

拓展：if so 如果這樣的話

if not 如果不是的話

if any 如果有的話

if necessary 如果必要的話

if ever 如果曾經(jīng)有的話

[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“如果這樣的話”。

2．John was_studying in his room when he heard screaming. 約翰正在屋里學習，突然聽到一聲尖叫。

when 并列連詞，意為“這時”，相當于 and then. when 作并列連詞用時，構(gòu)成并列句，意為“就在這時，恰恰在這時”，多用在下列句型中：

...be doing...when... 正在……這時……

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

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

had just done...when... 剛做了……這時……

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

①He was sleeping when there was a knock at the door.他正在睡覺，這時有人敲門。

②I was about to go out when someone knocked at the door. 我剛想出門，這時有人敲門。

③We had just begun to work when the machine broke down. 我們剛開始工作，這時機器壞了。

④The thief was on the point of putting his hand into the lady‘s handbag when the bus suddenly stopped.小偷正要把手伸進那位女士的手提袋中，這時公共汽車突然停了。

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

A．a(chǎn)s B．while C．when D．suddenly

答案：C

解析：句意為：孩子們正在操場上高興地踢足球，這時天開始下起大雨。