火灾一般可分为()个阶段。
A.1
B.2
C.3
D.4
参考答案:D
—How long _______ at this job?
—Since 1990.
A.were you employed
B.have you been employed
C.had you been employed
D.will you be employed
美国“宪法之父”是()
A.华盛顿
B.麦迪逊
C.林肯
D.罗斯福