当一架涡轮驱动的发动机调机去修理一个故障发动机时，必须遵守哪个操作规定？
参考答案：只有所需的机组成员才能上飞机。
具有抗癌活性的化合物是
A．甘草酸
B．雷公藤内酯
C．紫杉醇
D．薄荷醇
E．丹参酮
If you first aid correctly, the man would have not hurt that much. [ ]
A. had done
B. have given
C. did
D. gave
