Ⅱ.重點(diǎn)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(yǔ)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(xué)習(xí)，突然聽(tīng)到一聲尖叫。

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

...be doing...when... 正在……這時(shí)……

...be about to do...when... 正打算做……這時(shí)……

be just going to do...when... 正要……這時(shí)……

had just done...when... 剛做了……這時(shí)……

be on the point of doing...when... 正要……這時(shí)……

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

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

③We had just begun to work when the machine broke down. 我們剛開(kāi)始工作，這時(shí)機(jī)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(jìn)那位女士的手提袋中，這時(shí)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(chǎng)上高興地踢足球，這時(shí)天開(kāi)始下起大雨。