代表硬件防火墙接口最高安全级别的参数是
A.security 50
B.security 100
C.security 10
D.security 0
参考答案:D
正常二尖瓣开口面积为 ()
A.4~6cm2
B.2~4cm2
C.3~4cm2
D.1~2cm2
E.6~8cm2
We cannot figure out __quite a number of insects, birds, and animals are dying out.[ ]
A. that
B. as
C. why
D. when