Listening to loud music at rock concerts caused hearing loss in some teenagers

This is my dear teacher without_________help I couldn’t have passed that difficult exam.

We had better not bother our professor these days, for he is awfully busy preparing a report _____ atan international conference next month.[ ]

I play _____ basketball and play ______ piano every day.

Though most people are ____ the dangers of driving after drinking, many still insist on drinking alcohol.