弹簧垫圈未压平或螺栓松动，弹簧垫圈断裂或无弹性，属于失爆现象。
参考答案：对
______ for the boy to talk with his mouth full!
A．What bad manners they are
B．How bad manners they are
C．What bad manners it is
D．How bad manners it is
可治痹痛、疥癣的是
A．麝香
B．牛黄
C．冰片
D．苏合香
E．菖蒲
