检查盐酸普鲁卡因中特殊杂质对氨基苯甲酸时，采用以下哪种方法
A．TLCB．HPLCC．UVD．酸碱滴定E．亚硝酸钠滴定法
参考答案：A
中国石化加油站储油罐清罐周期为（）
A.1-2年
B.7-9年
C.10年
D.3-5年
Which of the following statements is FALSE ()
A. Hedgers trade to reduce some preexisting risk exposure.
B. The clearinghouse guarantees that traders in the futures marker will honor their obligations.
C. If an account rises to or exceeds the maintenance margin, then the trader must deposit variation margin.
