They ______ on the program for almost one week before I joined them, but still no good results _______ so far.
| A．had worked ; come out | B．have worked ; came out |
| C．had been working ; have come out | D．have been working ; have come out |
---Mike must have known that.
---No, he ________. How _______ he?
| A．mustn’t, must | B．may not, might | C．couldn’t, can | D．needn’t, need |
All the essays _____________, the teacher sent the students home.
| A．having written and collected | B．having been written and collected |
| C．being written and collected | D．to be written and collected |
---I was trying to carry out the plan, but I failed.
---Well, you _________, for we were uncertain it would do ________.
| A．needn’t do that, in fact | B．needn’t have done, in effect |
| C．needn’t have, in practice | D．needn’t, in time |
Up till now, full use of this theory has been ________ in building large ocean-going ships.
| A．done | B．made | C．laid | D．taken |
If I hadn’t stood under the ladder to catch you, you _________ now.
| A．wouldn’t be smiling | B．couldn’t have smiled |
| C．won’t smile | D．didn’t smile |