异戊二烯进行定向聚合,理论上可以产生()立构规整化合物。
A、2种
B、3种
C、5种
D、6种
参考答案:D
—Really,I don’t know_______to join the army or to find a job after my graduation.
—Why don’t you_______ your parents’ advice? They will surely help you.
A.if;take
B.whether;follow
C.if;give
D.whether;seek
偏头痛间歇期不宜用()
A.苯塞啶
B.心得安
C.甲基麦角酸丁醇酰胺
D.氯压啶
E.麦角胺咖啡因