_青島成考網

56.（）

Since computers were introduced, they____ to be useful tools for people weak in math.

• A、had proved

• B、have proved

• C、 will prove

• D、are proving

According to Paragraph 2, which of the following may lead to insomnia?

• A、Reading a book for relaxation before bedtime.

• B、Lowering lights one hour before bedtime.

• C、Drinking some warm milk before bedtime.

• D、 Listening to rock music before bedtime.