下列各句中，没有语病的一句是（ ）

I had thought he would be nervous in this speech competition, but he turned out to be calm.— He_____ quite enough preparation for it. [ ]

Only by shouting at the top of his voice _______ .[ ]

People should stop using their cars andstart using public transport— _______The roads aretoo crowded as it is

With a report _____ about the accident, the policeman has to find some witnesses for help.