----He is fluent in English because he once stayed in London ．
---- Really ? How long _________ there ?
| A．did he live | B．has he lived | C．had he lived | D．does he live |
．—Alice, you look puzzled．Haven’t you understood it?
—Yes．I _of another problem just now．
| A．had thought | B．have thought | C．thought | D．was thinking |
．—I can’t imagine Phelps was caught smoking on campus!
—_______．
| A．Nor am I | B．So do I | C．Me, too | D．Me, neither |
By looking at a problem in as many ways as possible, creative thinkers can find solutions that would _______ remain invisible．
| A．otherwise | B．yet | C．already | D．forever |
—What has made him upset recently?
—_______ alone to face a troublesome milk case．
| A．Left | B．Being left | C．Having left | D．To leave |
—What are you doing, John? Why stop?
—To be on the safe side, we’d fill up the car now for we _______ run out of gas on the way．
| A．must | B．will | C．might | D．should |