1 . ______ is acknowledged to us all that the old scientist, for whom life was hard in the past, still works hard in his eighties. (用适当的词填空)

2 . It suddenly occurred to him _____ he had left his keys in the office.

3 . The other day, ________ occurred to Johnson that he should make a road trip to help the needy. (用适当的词填空)

4 . Susan made________ clear to me that she wished to make a new life for herself. （用适当的词填空）

5 . _____is known to us all that the 2022 Olympic Winter Games will take place in Beijing. (用适当的词填空)

6 . _______ suddenly occurred to him that he had left his keys in the office.

7 . I’d appreciate ___________ if you keep silent. (用适当的词填空)

8 . I would appreciate ________ if you could keep silent. (用适当的词填空)

9 . You may rely on ________ that it won’t happen again. (用适当的词填空)

10 . He owes ____________ to his father that he has been so successful. (用适当的词填空)