木质楼梯的踏步板和踢脚板分别固定于（）上。
A.三角木
B.斜梁
C.护墙板
D.立柱
参考答案：A
若cosθ＞0且tanθ＜0，则θ所在的象限为______．
A circular rim 28 inches in diameter rotates the same number of inches per second as a circular rim 35 inches in diameter. If the smaller rim makes x revolutions per second, how many revolutions per minute does the larger rim make in terms of x ？（）
A.A
B.B
C.C
D.D
E.E
