转动着的叶轮和泵壳之间有间隙存在，漏失量最大可达总液量（）。
A.l％
B.3％
C.5％
D.8％
参考答案：C
Look! The children are listening _____ their teacher carefully.
A．for
B．to
C．at
D．in
Mary spends a lot of money on clothes ______ her family is not rich. [ ]
A. because
B. though
C. if
D. so
