—How many birds can you see in the trees?    

—I can see ________birds in them.       [ ]

A. hundreds of               

B. five hundreds      

C. hundred of                

D. five hundreds of

去甲肾上腺素作用最显著的组织器官是

A．眼睛

B．腺体

C．胃肠和膀胱平滑肌

D．骨骼肌

E．皮肤、黏膜及腹腔内脏血管