The shop manager always says to his clerks,“We can never be___________ polite to our customers.”

A.so

B.fairly

C.too

D.rather

答案及解析： C

解析：

can never be too polite“无论怎么礼貌都不为过”或者“越有礼貌越好”。can not(never)…too…再怎样也不过分。