—Must I turn off the gas after cooking?

—Of course.You can never be ________ careful with that.

A．enough

B．too

C．so

D．very

原发性肺脓肿最常见的病原菌是

A．金黄色葡萄球菌
B．肺炎球菌
C．厌氧菌
D．真菌
E．链球菌