高中英语语法-几种容易混淆的时态比较（二）之二

　　几种容易混淆的时态比较（二）之二

　　bsp; be back

　　 fall asleep/go to sleep be asleep

　　1. 他已出去了。他出去了好几个小时了。

　　 2.他已睡着了。睡着了好一会儿了。

　　 ２、make sure/be sure表示采取措施以保证之意时，从句中的时态用一般时或完成时。

　　 1.Make sure that you ______(turn) off the light when you leave.

　　 离开时务必关灯。

　　 2.Make sure that you ________(finish) the work before six.

　　 务必在六点前结束工作。

　　 3.The hunter held his hand tightly to be sure that he didn't bow,either.

　　 那位猎人紧握他儿子的手，以使他也不低头鞠躬。

　　 ３、在时间状语或条件状语从句中，用一般现在时或现在完成时表示一般将来时，一般过去时或过去完成时表示过去将来时。

　　 1.Tell him about that when he _______(come).

　　 2.His daughter won't go to bed until she _______(finish) her homework.

　　 3.We would get into trouble as soon as the gas _______( run ) out.