The parents rushed to the hospital ____ they heard that their son was injured. [ ]

下列各句中，没有语病的一句是

I enjoy playing computer games, but I can’t ______ too much time ________ that.

By the way, how many of us canattend the meeting —The number of thestudents to attend the meeting _____ fifty.

I want someone to write the composition for me. — No. As a student, you ____depend on yourself.