It's a waste of time......................... (think)about how things might have been.
举一反三
- –What do you think the noise was? –It (__) a cat. A: may be B: might be C: could have been D: might have been
- — How many times have you been to America — It’s the second time I ______ there. A: was B: am C: have been
- Things might have been much worse if the mother ( ) on her right to keep the baby.
- ______ a little more time to think, he might have acted much better.
- How about the man’s plan A: I have finished it. B: It’s not finished. C: It has been finished.