for sb to do sth用作主語

for sb to do sth在句子中可有作主語。如：

For you to ask Joe would be a big mistake. 你要是去問喬，那將是一大錯誤。

For Ann to go to France would make me very happy. 安要是到法國去將使我感到很高興。

注：這類結構通常會借助形式主語來表達，即在句首使用形式主語，而將真正用作主語的“for+賓語+不定式”結構移至句末。如：

It’s too expensive for me to buy. 太貴了，我買不起。

It’s impossible for me to leave my family. 我是不可能離開家的。

It’s impossible for the job to be finished in time. 這項任務要按時完成是不可能的。

It’s an honour for me to be asked to speak here. 我很榮幸被邀在這里講話。

It’s a new experience for her to be travelling by plane. 坐飛機對她是—次新經歷。

It’ll take time for her to recover from the illness. 她的病要很長時間才能痊愈。

It took twenty minutes for the smoke to clear. 過了20分鐘煙才散完。