I want to be left alone ___ things out.
| A．think | B．thought | C．thinking | D．to think |
-----Did Mary come to the party?
---I don’t know．She _____while I was out．
| A．may have come | B．must have come |
| C．might come | D．could come |
The old man leads ______happy life now, but he will never forget ______hard time when he was poor.
| A．the, a | B．/; the | C．the; / | D．a, the |
---I regret _____you John has been fired．
---I can hardly believe my ears．He’s such a fine worker．
| A．telling | B．having told | C．to tell | D．to have told |
---Alice, you look puzzled, Have you understood it?
---No．I _____another problem just now．
| A．l have thought of | B．am thinking of |
| C．had thought of | D．was thinking of |
How pleased the detective was _____what his customer told him!
| A．hearing | B．to hear | C．heard | D．to hearing |