This is ________ apple.[ ]
A. a
B. an
C. the
D. /
答案：B
We did everything we could________ him to stay,but he insisted on leaving. [ ]
A. try to persuade
B. to try to persuade
C. try persuading
D. to be persuaded
近年来输血后肝炎主要由哪种病毒引起
A．甲型肝炎病毒
B．乙型肝炎病毒
C．丙型肝炎病毒
D．丁型肝炎病毒
E．戊型肝炎病毒
