行车中当车辆前轮爆胎已发生转向时，驾驶人应双手紧握转向盘，尽力控制车辆直线行驶。
参考答案：对
With the help of high technology, more and more substances _________ in the past years.
A．discovered
B．have discovered
C．had been discovered
D．have been discovered
急性颜面或下肢感染伴发热，病变呈鲜红色，边缘稍隆起，与正常皮肤界限清楚，指压可使红色消退，压力除去后红色很快恢复。最可能的诊断是
A．急性淋巴管炎
B．气性坏疽
C．深部脓肿
D．丹毒
E．浅静脉炎
