Bob would have helped us yesterday, but he_______
| A．was busy | B．is busy | C．had been busy. | D．will be busy |
After thirty years of separation, I _____ with my sister. How happy we were!
| A．kept in touch | B．caught up | C．kept up | D．got in touch |
--- Have you seen the robber______?
--- Why ask me? You are the only one who stands _____ to him.
| A．clear; close | B．clearly; closely | C．clear; closely | D．clearly; close |
Only when I left my parents for Italy _____ how much I loved them.
| A．I realized | B．I had realized | C．had I realized | D．did I realize |
Some researchers believed that there is no doubt______ a cure for AIDS will be found.
| A．which | B．what | C．that | D．whether |
--- I started off to walk, but Peter gave me a lift.
--- Therefore, you _____ after all.
| A．didn’t need walk | B．needed not walk |
| C．didn’t need to walk | D．need not to walk |