The flu is believed _____by viruses that like to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused | C．to be caused | D．to have caused |
Dela had made up his mind to give it up ,but on _____ second thought ,he determined to try ______ third time．
| A．/; a | B．/ ; / | C．a ; a | D．the ; a |
-I'm sorry I'm late again But I…．
-It's 'no use_______. It's the third time that You came late this week
| A．complain | B．complained | C．to complain | D．complaining |
_______ the TV, Tom began to read newspaper.
| A． Turned off | B．Turn off | C． To turn off | D． Having turned off |
-Did you catch the first bus?
-No ,it_______ the stop by the time I got there.
| A．left | B．was leaving | C．had left | D．would leave |
______the boy has already corrected his mistake, we should not punish him any more.
| A．Since | B．Until | C．Unless | D．Although |