生物碱的磷酸盐不能用高氯酸直接滴定。（ ）
参考答案：错
She hasn't got enough money ______ she buys the rings. [ ]
A. for which
B. with which
C. that
D. which
万用表能用来测试以下哪个值（）
A.频率
B.误码率
C.直流电压
