It引起的几个易混淆的时间句型.docVIP

It引起的几个易混淆的时间句型 在学习中，同学生们对“It + be + 时间 + 从句”这个结构经常混淆不清，下面逐一进行分析。 1. It + be + 时间 + since-clause 这个句型表示从since 从句谓语动作发生以后到现在或过去所经过的一段时间，意为“自从......以来已多久了”，主句多用一般现在时，从句用一般过去时，如果表示过去的情况，主句用一般过去时，从句用过去完成时，或主句用过去完成时，从句用一般过去时。例如： It is three years since his father passed away . (从现在算起) It was 10 years since they married . (从过去算起) It had been fifteen years since she left Shanghai . (从过去算起) 30 years has passed since we joined the Party . (从现在算起) 2. It + be + 时间 + before-clause 这个句型中的时间一般为表示一段时间的词语(如：long years , months , weeks , days ,hours , minutes ) ，主句中的谓语动词用肯定式，意为“过多长时间才......”。主句的谓语动词是否定式时，意为“没过多长时间就......”。主句的时态可用过去时was或将来时will be；用was 时，before从句的动词用一般过去时；用will be 时，before从句常用一般现在时。 例如： It was not long before she learned those poems by heart . 她没过多久就背会了那些诗歌。 It was long before the police arrived .过了很久警察才来。 It will be hours before he makes a decision . 要过好几个小时他才会作出决定。 It will not be hours before meet again . 要不了几个小时我们还会再见面的。 3. It + be + 时间 + when-clause 这个句型中, it 指时间，而且表示时间的词语前没有介词(时间一般为具体时间)。主句中的谓语动词和从句中的谓语动词在时态上一般是一致的，主句是will be，when从句用一般现在时代替将来时。例如： It was already 8 o‘clock when we got home . It was the next morning when we finished our work . It will be midnight when they get there . 4. It + be + 时间 + that-clause 这个句型是个强调句型。例如： It was two years ago that he made an important invention . (原句是：He made an important invention two years ago . ) It was at 5 o’clock that he practised playing the violin in the morning . (原句是：He practised playing the violin at 5 o‘clock in the morning . ) 比较：It was 5 o’clock when he started in the morning . (5 o‘clock前没有介词，这是个定语从句) 5. It + be + time + that-clause 这个句型属虚拟语气结构，不管主句中用的是 is 或 was ，that从句都须用动词的过去式或should + 动词原型(但不及用过去式普通)，在time之前有时可加上high或about 以加强语气。例如： It is time(that)we handed in our exercises .(= It is time that we should hand in our exercises .) It is high time (that ) she wrote a letter to her boyfriend . 6. It / This / That + the first(second , third …) time +