同城票据交换80383交换提出场次修改交易能对单笔票据进行（）的场次切换
A、上移一场
B、下移一场
C、上移一场或下移一场
D、随意场次
参考答案：C
—Look at the boy running on the ground. Is it David?
—It _____be him. I saw him go to the teacher's office just now. [ ]
A. might
B. could
C. can't
D. mustn't
花粉粒类球形，表面有类似网状雕纹的是( )
A．红花B．蒲黄C．西红花D．洋金花E．丁香
