莱菔子、车前子清除杂质常用的方法是（）
A.挑选
B.筛选
C.水选
D.风选
E.浸漂
参考答案：A
5.4等于几个百分之一？[ ]
A．54
B．540
C．5400
Most people find it hard to ________Beijing Opera to foreigners because of cultural differences.
A．get across
B．get over
C．come across
D．come over
