细粒式沥青混合料多用于（）
A.基层
B.面层下层
C.单层式沥青面层
D.沥青面层的上层
参考答案：D
____ has recently been done to provide more buses for the people, a shortage of public vehicles remains a serious problem.
A．That
B．What
C．In spite of what
D．Though what
非晶
