在砂土按密实度分类中，标准贯入击数15（）
A.密实砂土
B.极密实砂土
C.中密砂土
D.稍密砂土
参考答案：C
热拌热铺沥青混合料适用于( )公路的沥青面层。
A．一级 B．二级C．三级 D．各种等级
-We all had a lot of fun at the barbecue yesterday. Pity you weren't there.
-I really should have gone with you but I ________ on some important problems.[ ]
A．worked
B．was working
C．would work
D．would have worked
