推土机在上坡途中,当内燃机突然间熄灭,应立即(),并锁住制动踏板。在分离主离合器后,方可重新启动内燃机。
参考答案:放下铲刀
—Mummy, can I ride your new motor bike to school?
—Sorry, dear! You are too _______ to do that. [ ]
A. quiet
B. old
C. brave
D. young
临床可用于预防艾滋病病毒的母婴传播和治疗艾滋病的药物是()
A.碘苷
B.阿昔洛韦
C.沙奎那韦
D.利巴韦林
E.金刚烷胺