汽油发动机发生爆震时，放松油门即可减轻或不产生爆震，表示点火时间过早。
参考答案：对
这是什么踏板？（）
A．加速踏板
B．离合器踏板
C．制动踏板
D．驻车制动器
Lucy was ill, so she had nothing for breakfast, ________?[ ]
A. did she
B. had she
C. hadn't she
D. didn't she
