常考知识点一：动词的时态和语态

	现在	过去	将来	过去将来
一般	do/does	did	shall/will do	should/would do
进行	am/is/are doing	was/were doing	shall/will be doing	should/would be doing
完成	have/has done	had done	shall/will have done	should/would/ could have done
完成进行	have/has been doing	had been doing	shall/will have been doing	should/would have been doing

　　易出现为在单选部分，需要判断动作发生的时间，与句子中所强调的部分。尤其是主句和分句之间的时间关系。注意运用正确时态。黑体部分最常考。

　　【单选】The glass remains warm because you ( ) it since this morning.

　　A. held

　　B. holding

　　C. hold

　　D. have been holding

　　【答案】D。“因为你一早上都拿着这个杯子，这个杯子现在还是暖的。”该题出现了由because引导的原因状语从句，所以because后面应出现完整的句子，即主谓宾，空白处必须是谓语，而B是非谓语，所以排除B;题干since this morning(从今天早上起)，从过去的某一时间点延续到现在(因为主句用的是一般现在时)，所以必须要出现现在完成时，而D项的现在完成进行时是现在完成时中的一种，特殊之处在于它还表明某种情况将会继续进行，也符合该题义，所以正确答案为选项D。