与其它防腐层相比，石油沥青防腐层（）。
A.技术难度大
B.价格昂贵
C.吸水率高
D.不易受细菌腐蚀
参考答案：C
Pauwells角
It doesn't matter ________ you pay by cash or credit card in this store . [ ]
A. how
B. whether
C. what
D. why
