离子交换树脂用的交联聚苯乙烯白球采用（）聚合方法，可发性聚苯乙烯采用（）聚合方法。
参考答案：悬浮； 悬浮
а为锐角，且sinа=0.6，则（ ）
A．0°＜а＜30°
B．30°＜а＜45°
C．45°＜а＜60°
D．60°＜а＜90°
—My football socks are _____ out.
—How long have you _____ them? [ ]
A. worn; bought
B. wearing; had
C. wearing; bought
D. worn; had
