最擅长摔跤、射箭、赛马体育项目的少数民族是：[ ]
A．藏族
B．傣族
C．蒙古族
D．维吾尔族
答案：C
—Shall we________to attend the meeting________at the end of this month?
—Sorry, I don't know.[ ]
A. ask; holding
B. ask; to hold
C. be asked; held
D. be asked; to be held
A．改变双缝到屏的距离，条纹间距不变
B．入射光的强度改变，波长不变时，条纹间距会随之改变
C．入射光的频率改变时，条纹间距会随之改变
D．在水里做双缝干涉实验，比在空气中做条纹间距会大
