下列各句中，没有语病的一句是（ ）

Sandy could do nothing but _________ to his teacher that he was wrong

People say that young Chinese students’ eyesightkeeps dropping _________ because of both too much homework and poor learningconditions.

reasonsfor my decision to become a university professor, my father’s advice was mostimportant one

John opened the door. There _____ he had never seen before.