空气冷却器结构中可以直接作为调节装置的是（）。
A.百叶窗
B.风机
C.管束
D.框架
参考答案：A
-----Do you know__________________?
-----At the end of July?
A．how soon is your sister coming back home
B．how often Nancy hears from her pen friend
C．when the London Olympic Games will be held
D．when will the new computer game come out
生物毒性作用
