狀語(yǔ)從句（一）
回家之前我必須干完所有的活。
you must first learn to walk before you try to run.
在想要跑以前，你得先學(xué)會(huì)走。
he had learned english for three years before he went to london.
他去倫敦之前已學(xué)了三年英語(yǔ)。
提示：
before 從句往往帶有否定的含義。
he ran off before i could stop him.
我還沒(méi)來(lái)得及阻止他，他就跑掉了。
thke it down berore you forget it.
趁著還沒(méi)忘記的時(shí)候就記錄下來(lái)。
必背：
before 常用句型 it is was will be �before�
it wil be five years before we meet again.
五年以后我們才能再見(jiàn)。
it will be not long before you regret what you have done.
不用過(guò)多久你就會(huì)對(duì)你所作所為感到后悔的。
it was not long before i realized i was wrong.
不久我就意識(shí)到我錯(cuò)了。
it was minutes before the police arrived.
過(guò)了幾分鐘警察才到。
2.after
after表在一段時(shí)間之后。
let's play football after school is over.
放學(xué)后我們踢足球吧。
the sun came out soon after the storm stopped.
暴風(fēng)雨過(guò)后不久，太陽(yáng)出來(lái)了。
c.till, until
1.untiltill用于肯定句時(shí)，表示直到 為止，主句必須為持續(xù)性動(dòng)詞。
we shall wait until till he comes back.
我們將一直等到他回來(lái)。 (注意它們的拼寫(xiě))
everthing went well untiltill that accident happened.
直到發(fā)生那意外之前，一切都正常。
2. not�untiltill表示直到 才 ，主句通常要用短暫動(dòng)詞，這時(shí)until和till可用before代替。
i didn't leave until till before she came back.
直到她回來(lái)，我才離開(kāi)的。
bells don't ring till until you strike them.
鈴不打不響。
peopl do not know the value of their health till until before they lose it.
人們直至失去了健康才知其可貴。
3.當(dāng)not until位于句首時(shí)，主句中的主語(yǔ)、謂語(yǔ)要使用倒裝語(yǔ)序。
not until she stopped crying did i leave.
直到她不哭了，我才離開(kāi)的。
注意：
until引導(dǎo)的從句可以放在主句之前或主句之后，但till從句一般不放在句首。
4.在強(qiáng)調(diào)句型中一般只能用until，不用till。
it was not until she took off her drk glasses that i recognized her.
直到她摘下墨鏡，我才認(rèn)出她。
d.since, ever since
1.since自……以來(lái)。表示動(dòng)作從過(guò)去某一點(diǎn)時(shí)間一直延續(xù)到說(shuō)話(huà)時(shí)間為止。主句中通常為延續(xù)性動(dòng)詞的現(xiàn)在完成時(shí)，since從句中一般用短暫性動(dòng)詞的一般過(guò)去時(shí)。
it has been just a week since we arrived here.
我們到這兒剛剛一星期。
where haveyou been since i last saw you
自上次我見(jiàn)過(guò)你之后，你去了哪里？
since she was young, she has been collecting stamps.