Several minutes after its launch, the X-37B plane successfully sent back its first___________to the control center.
| A．mark | B．sign | C．instruction | D．signal |
Sarah ______ change her mind, even though she knew the plan was hard to carry out.
| A．mustn’t | B．wouldn’t |
| C．shouldn’t | D．needn’t |
I was made ______ four hours before I was examined by a doctor, which was really annoying.
| A．wait | B．waiting |
| C．being waited | D．to wait |
George always does his best in school, and that’s ______ I like about him.
| A．where | B．why | C．how | D．what |
Extra boiling water should be kept at hand just ______ it is needed.
| A．as | B．because |
| C．in case | D．as if |
– You left your umbrella.
– ______. I’m becoming so forgetful these days.
| A．So did I | B．So I did |
| C．So was I | D．So I was |