与四氢硼钠反应呈紫色的是
A.二氢黄酮
B.生物碱
C.黄酮醇
D.异黄酮
E.黄酮
参考答案:A
解析:四氢硼钠(NaBH4)是对二氢黄酮类化合物专属性较高的一种还原剂。
They had not finished their homework in time, so they tried to avoid_____ by copying answers. [ ]
A. being punished
B. punishing
C. to punish
D. punished
根据下面的数据段定义可知,变量DAT的偏移地址是( )。 DSEG SEGMENT DAT DW 'AB', 'CD', 'EF', CNT EQU $-DAT DSEG ENDS
A.03H
B.04H
C.06H
D.07H