灭火器B类火灾配置场所的危险等级为严重危险级时，推车式灭火器的最大保护距离为()m。
A．15
B．18
C．20
D．25
参考答案：B
Our school basketball match will be held from October 12th to 16th, during time as many as 30 teams will compete for the championship.
A．which
B．whose
C．when
D．that
从所给的四个选项中，选择最合适的一个填入问号处，使之呈现一定的规律性。（）
A.A
B.B
C.C
D.D
