It will be +时间段+before+一般现在时的从句 “要过多久/ 不久…才…”
It was +时间段+before+一般过去时的从句 “过了多久才…” “before”句型和“since”句型的共性都加时间段,差异在于前后的时态和翻译。
① It will be ten years before I return home. 译为:要过十年我才能回家.
② It was ten years before he found his lost boy. 译为:过了十年他才找到了他失踪的儿子.
1、It is reported that it may be two or three months_____it is possible to test this medicine on animals.
A:since B:after C:before D:when
2、－How long do you think it will be ______ China sends a manned spaceship to the moon？
－Perhaps two or three years
A:when B:until C:that D:before
3、How long do you think ____ the computer company brings out a new product？(2005.上海)
A: it will be before B:will it be until C:will it be when D: it will be that
【答案:1、C 2、D 3、A】