隔爆设施安装时袋底距地面应≥（）m。
A.2.0
B.1.8
C.1.6
D.1.2
参考答案：B
As early as 1647 Ohio made a decision that free, tax supported schools must be established in every town _____ 50 households or more.
A．having
B．to have
C．to have had
D．having had
投资中心
