节流阀的结构与（）属同一类别，主要区别是阀芯的形状不同。
A.调压阀
B.止回阀
C.截止阀
D.减压阀
参考答案：C
从方框内选择合适的单词填空，使文章通顺、完整。（每词限用一次）
friends, watch, same, tennis, plays, for, and, thinks, loves, doesn’t
I have four good小题1:______. They’re Jennifer, Victor, Cindy and Leila. We are in the小题2:______class. So we’re classmates, too. Jennifer loves小题3:______, she has 7 tennis rackets. She always小题4:______it with me. Victor小题5:______to小题6:______TV. She小题7:______like sports. She小题8:______sport is difficult小题9:______us. Leila小题10:______Cindy have the same ideas（观点）.
屋面细石混凝土防水层混凝土水灰比不应大于（）。
A.0.4
B.0.6
C.0.55
D.0.45
