材料的耐水性可用（）表示。
A、亲水性
B、憎水性
C、抗渗性
D、软化系数
参考答案：D
— I saw you come to school on foot this morning.
— Yes. My bike . [ ]
A. is mending
B. is being mended
C. is mended
D. is being mending
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