【简介】感谢网友“雕龙文库”参与投稿，这里小编给大家分享一些，方便大家学习。
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.
