压力式滤器，制作开缝式排水支管时，应选用（）作材质。
A.碳钢
B.硬聚氯乙烯
C.不锈钢
参考答案：C
_____ she is ill, _____ she goes to school.[ ]
A. Although; /
B. Although; but
C. But; although
D. Because; /
简述下肢假肢接受腔最常用的材料。
