In college, Spring Break is usually associated with the beach, parties and sleepless nights,______ about relaxation and free time．

A．bring

B．brought

C．bringing

D．to bring

地下、半地下和高层汽车库、甲、乙类物品运输车的汽车库、修车库和Ⅰ类汽车库、修车库的耐火等级不低于（）。

A.一级

B.二级

C.三级

D.四级