Unit3 The Computer and the Information Age-grammar教案
时态一。总述： 为了便于讲解，我将英语中的时态，分为现在时和过去时。现在时包括一般现在时，现在进行时，现在完成时，姑且把将来时也归入此类。过去时包括，一般过去时，过去进行时，过去将来时，过去完成时。一般来说，时态对应是指现在时对应现在时，过去时对应过去时。当然，特殊语境需要特别分析。二。时态对应主要包括以下的典型用法。1。下列情况下，如果主句是将来时《用will/shall/can/must/》或者主句是祈使句，从句用一般现在时。1》在 if /unless/ even if/ 引导的条件状语从句中.如：you will be punished unless you go though with the work.i won't attend the party even if i am invited.2》在when/before/until<till>/as soon as/the moment/ once/引导的时间状语从句中。如：i'll let you know the moment i get timely information.once you realize your mistake, you'll regret for what you've done.3》在 no matter what/no matter who/no matter when/no matter where/no matter how/no matter which/或者 whatever/whoever/whenever/wherever/however/whichever 引导的让步状语从句中。如：i'll believe whatever you have said.however difficult the problem is ,we'll overcome it .wherever you go,i'll follow you.we can help whoever gets in trouble.2。在 祈使句+and/or+句子 的模式中，and/or 后的句子常用将来时态。如：put on the coat,or you'll catch a coldwork hard,and you'll make rapid progress.3。注意used to/would 区别。他们都表示过去常常。但would 常和时间连用，而used to 不可以。如：when i was a boy, i would swim every day.<不用used to>4.be about to do 如果用在简单句中，常用一般现在时。如果用在复合句中，常和when 引导的过去时的从句连用。如：i am about to leavewhen i was about to fall asleep when someone knocked the door.但要注意be about to do 不和具体的时间连用。我们不可以说，we are about to leave this afternoon ,应说，we are about to leave或者说，we will be leaving this afternoon.5.语境中的过去时常表示“刚刚，刚才”之意，暗示现在已经不是这样..如：sorry,i didn't know you were here .6.表示愿望，打算一类的词，如hope, expect, mean, intend, want, think, suppose, want 等，其过去完成时表示过去未曾实现的愿望或意图。如：----why haven't you attended the party?---i had meat to,but i was busy.7.在 it/this be the first/second/---time+that 句中。如果be 为一般现在时，that后的句子一般用现在完成时或一般现在时，如果 be为一般过去时，that后的句子为过去完成时。如：this is the first time that i have met the famous scientist.this is the first time that he gets involved in the tournament.8.在 it be +段时间 +since 从句中，如果be 表现为 is或has been 形式，since 从句用过去时，如果be 表现为was 或 had been,从句用过去完成时。如：
