What was the___of the accident?

What was the___of the accident?
A.reason B.cause C.way D.answer
2.I___no sooner reached home than it began to rain.
A.have B.has C.had D.不填
3.The salesman persuaded us___his product.
A.buy B.to buy C.buying D.bought
4.You should___the fire before going to bed.
A.put away B.put up C.put off D.put out
5.It took them a long time___the problem of pollution.
A.to solve B.solving C.solved D.solve
6.——What is Tom doing? ——He is busy___his new movie.
A.for B.in C.with D.from