2018年公共英语三级语法学习技巧：时态
时态
英语是时态是一种动词形式，是用动词的各种变化形式表示动作发生的时间。英语共有十六种时态，答题时我们要特别注意一些时态的标志词。下面以经常考察的完成时为例子进行讲解。
经典考题
1. Ever since Picasso’s painting went on exhibit, there large crowds at the museum every day.
A) is B) have been C) has been D) are being
2. This is the second time he Mr. Smith.
A) had seen B) has seen C) sees D) saw
3. By the end of this month, we surely a satisfactory solution to the problem.
A) have found B) will be finding
C) will have found D) are finding
4. Before the first non-stop flight was made in 1949, it necessary for all planes for refueling.
A) would be B) has been
C) had been D) would have been
考点分析
动词完成式包括现在完成时、过去完成时、将来完成时、过去将来完成时，前三种是方法测试的重点，其考点如下：
1. 关于现在完成时应注意以下几点：
1)注意与现在完成时相关的状语。如：since、for、this year、today等，或表示不确定概念的副词，如：already、often、never、so far、yet、always等。另外，某些瞬时动词如ask、begin、come、die、join等，不能跟表示一段时间的状语连用。
2)在“this is +最高级/序数词/ the only+名词+that”结构中， that 从句中的谓语在完成时。例如：
This is the best wine I have ever drunk.
This is the first time I have visited China.
2.将来完成时表示某时以前已经完成的动作。注意与此时态连用的时间状语the end of…、by this time tomorrow、by then 等，例如：By this time tomorrow you will by home. 另外，在时间或条件状语从句中，现在完成时也可以表示将来完成时。例如：your paper when you have finished the test.
3.过去完成时应注意以下几点：
1)过去完成时表示过去某一时间或动作之前完成的动作，常用的确状语有just、ever、by that time、by the end of…、before等。例如：We had just had our breakfast when an old man came to the door.
2)动词 expect、hope、intend、mean、want、suppose等用过去完成时，表示过去的希望意图、愿望未实现。例如：They had intended to help, but couldn’t get here in time. (他们本来打算来帮忙，不过没来得及赶到这儿)
3)在“It was+最高级/序数词/ the only +that”结构的从句中，使用过去完成时，例如：There was a knock at the door. It was the second time someone had interrupted me that evening.
考题注释
① 本题题干中出现了一个时间状语since, 故应用完成时，又由于主句的主语large crowds 为复数形式，故排除C)。
② 在this is the second time…结构中，其后从句中的谓语用现在完成时。
③ 译文为：“到这个月底为止，我们肯定能找到解决问题的方法。”时间状语为by the end of this month , 故用将来完成时。
④ 本题中before 引导了一个时间状语从句，从句的谓语为过去时，由此推知，主句的谓语应是过去之过去，即过去完成时。
答案： 1.B 2.B 3.C 4.C
