不用if的條件從句結(jié)構(gòu)
在筆語中，條件從句有時可以不用連詞小而把were，had或should移至主語之前。但如從句沒有were，had或should，則一般不能這樣做。如：
Should he come，tell him to ring me up.他要是來了，讓他給我打個電話。
Were I in your position，I would go.如果我處于你的地位，我就去。
Had they not helped us，our experiment would have failed. 如果沒有他們的幫助，我們的試驗是會失敗的。
[注]有時虛擬條件不用條件從句而用介詞短語、動詞不定式等來表示。如：
without contradiction nothing would exist. 沒有矛盾就沒有世界。
We could not have done the work well without your help.要是沒有你的幫助，我們不可能做好這工作。
It wonld be a good idea to go swimming at the summer palace.到頤和園去游泳，倒是個好主意。
All this would have been impossible ten years ago.這一切在十年前是不可能有的。