The flu is believed________by virus that likes to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused | C．to be caused | D．to have caused |
On the flight to Chongqing, the memory of my childhood, _______ I was my father’s shadow, came flooding back．
| A．as | B．when | C．while | D．where |
．—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 |