1I’m amazedto hear from my school teacher again. _______，it is ten years since we met last.

The government of the United States began at once toinvestigate the case ______ a lot of students were killed.

Could you give me an explanation ______ your keeping silent throughout the discussion?-Oh, terribly sorryI had the least idea of what ________I would have made a complete foolofmyself if I had said anything[ ]

She always does very well in the English exams. Butshe can _____ understand English radio programs.

Are these Helen’s pencils—-Yes, they are _______.