腺苷酸环化酶将cAMP降解成AMP。 ( )
参考答案：错
可收缩结膜表层血管（）。
A.丁卡因
B.色甘酸钠
C.双氯芬酸钠
D.氧氟沙星
E.去氧肾上腺素
To learn English well, we should find opportunities to hear English______ as much as we can.
A．speak
B．speaking
C．spoken
D．to speak
