They have been waiting for many hours to see the singer, but the airplane must have been _____.
| A．behind the times | B．behind schedule | C．ahead of time | D．in no time |
Mary clapped her hand over her mouth _______ she realized what she had said.
| A．while | B．as soon as |
| C．suddenly | D．then |
_____ she goes, there are crowds of people waiting to see her.
| A．Wherever | B．however |
| C．Whichever | D．Whoever |
You should put on the notices ______ all the people may see them.
| A．where | B．in which |
| C．at | D．for them |
_____ I suggest, he always disagrees.
| A．however | B．whatever |
| C．Whichever | D．Whoever |
“Was his father very strict with him when he was at school?” “Yes. He had never praised him _______ he became one of the top students in his grade.”
| A．after | B．unless |
| C．until | D．when |