The association is ________ to raising funds to help the blind.

Since William had been seriously ill for several months, his parents were worried about________ to return to school full-time.

It ________ as a shock to realize that I was not alone in the room.

________ so many people in the United States been out of work as today.

When he suddenly ________ up the subject of genetic engineering, there was an embarrassedsilence.

The problem ________ when the students refused to do their homework.

This diploma ( 毕业文凭 ) ________ that you have completed high school.

To succeed in a scientific research project ________.

The more we looked at the picture, ________.

I know it isn ’t important but I can ’t help ________ about it.