should be doing是什么时态

过去进行时

should be doing 或者 was doing ,be doing been doing 他们都叫做进行时.

should 要接动词原形,但是这里的动词原形可不是表示现在进行时呀,

Be表示的是过去的时态.

所以应该在做什么（言外之意就是现在还没有做）

英语中有16种时态

1.一般现在时 the present tense

2.一般过去时 the past tense

3.一般将来时 the future tense

4.一般过去将来时 the past future tense

5.现在进行时 the present continuous tense

6.过去进行时 the past Continuous Tense

7.将来进行时 the future continuous tense

8.过去将来进行时 the past future continuous tense

9.现在完成时 the Present Perfect Tense

10.过去完成时 the Past Perfect Tense

11.将来完成时 the future perfect tense

12.过去将来完成时 the past future perfect tense

13.现在完成进行时 the present perfect continuous tense

14.过去完成进行时 the past perfect continuous tense

15.将来完成进行时 the future perfect continuous tense

16.过去将来完成进行时 the past future perfect continuous tense