选用 by, with, in, through, use填空.

1. He dug a hole in the ground _         his bare hands.

2. May I           your knife to cut my pencil?

3. He said          a low voice,"Go to your seat."

4. You can make a living       borrowing some money from your friends.

5. They have made much progress____   their hard work.

飞灰的磨损使受热面管壁（），强度（），造成破坏。