The two girls are so alike that strangers find________difficult to tell one from the other.
| A．it | B．them | C．her | D．that |
When Marx was in London, he _____ read at the library for hours.
| A．would | B．might | C．could | D．should |
Keep up good state of mind even if you _____ fail plenty of times.
| A．must | B．will | C．can | D．should |
— Are you coming to Jeff’s party?
— I’m not sure. I _____ go to the concert instead.
| A．must | B．would | C．should | D．might |
— Mary’s got mad and has been sent to the mental hospital. Did you tell her boss about that?
— Yes, but I _____ her husband first.
| A．should have told | B．shouldn’t have told | C．must have told | D．needn’t have told |
My English-Chinese dictionary has disappeared. Who _____ have taken it?
| A．should | B．must | C．could | D．would |