1 . I found ______ useless trying to talk him out of buying the expensive toy. (用适当的词填空)

2 . They should make ________ clear for us to know how to operate the machine.(用适当的词填空)

3 . He really felt ________ an honour to win the championship in the international competition.(用适当的词填空)

4 . I find _________ hard to remember these words in a short time. (用适当的词填空)

5 . She had failed for twice in the driving test, and finally made _____ on her third try.

6 . I’d appreciate________ if you could give us some advice on how to improve to our robot.（用适当的词填空）

7 . The high-speed rail makes ________ possible for passengers to travel much faster.（用适当的词填空）

8 . Sometimes he found ________ hard to fall asleep at night, so he went to see the doctor. (用适当的词填空)

9 . I make ______clear that I won’t give up the chance. (用适当的词填空)

10 . We find ____important to master a foreign language when we go abroad.（用适当的单词填空）