二级耐火等级的高层民用建筑，其吊顶的耐火极限不应低于()h。
A．0.1
B．0.25
C．0.15
D．0.2
参考答案：B
8-9+5×（-6）-12÷（-6）×3
A: Jim had nothing for breakfast this morning, ?
B: . He got up too late.
A．had he; Yes
B．hadn’t he; Yes
C．did he; No
D．didn’t he; Yes
