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

---The population of Henan ___________ very fast.

---I agree. The population problem may be one of the most serious ones today.

A．are growing

B．grew

C．is growing

D．is grown