由于气管、支气管解剖结构特点,支气管扩张易发生于()
A.左侧支气管
B.右侧支气管
C.两下叶支气管
D.前段支气管
E.上叶支气管
参考答案:C
If the firefighters ________ in time, the fire would have resulted in many deaths in the hotel.
A.wouldn’t have arrived
B.hadn’t arrived
C.didn’t arrive
D.shouldn’t arrive
计算液体的流量是把流过断面的面积与该液体的最大流速相乘。