在各种化学性致癌物中致癌谱广，致癌力又强的是（）
A.烷化剂
B.亚硝胺类
C.霉菌毒素
D.芳香胺类
E.氨基偶氮类
参考答案：B
—Can you hit that bird with your gun, Tom?
—No！It is out of the ________of my gun.
A．length
B．aim
C．distance
D．range
.
They ___ out because the light’s on. Let’s go upstairs and have a look.
A．mustn’t go
B．can’t have gone
C．couldn’t go
D．might have gone
