()是减轻摩擦磨损的有效手段。
A、紧固
B、清洁
C、润滑
D、防腐
参考答案:C
根据行波学说原理,基底膜底部主要感受()声波,基底膜顶部主要感受()声波。
When asked about their opinions about the schoolmaster, many teachers would prefer to
see him step aside ________ younger men. [ ]
A. in terms of
B. in need of
C. in favor of
D. in praise of