Question

By the time he realizes he ____ into a trap, it’ll be too late for him to do anything about it.

A．walks

B．walked

C．has walked

D．had walked

Answer 1

C

句意為：到他意識到已經(jīng)進入一個圈套的時候，對于他來說做任何事情也都為時已晚了。與by the time 連用的句子應該用什么時態(tài)， 主要是看這個時間點發(fā)生在過去還是現(xiàn)在或將來。句中he realizes是現(xiàn)在的時間點，所以要用現(xiàn)在完成時，如By the time he is ten, he has outgrown his older brother. 他十歲的時候就已經(jīng)長得比他哥哥高了。D項一般是從句為一般過去時的時候，主句才用過去完成時。