A:had known, would not be
B:had known; wouldn’t have bee
C:knew; would not have bee
D:had known; would never be
春节期间人们放飞孔明灯表达对新年的祝福,如图所示,孔明灯在竖直Oy方向做匀加速运动,在水平Ox方向做匀速运动,孔明灯的运动轨迹可能为( )
和珠江三角洲相比,港澳的优势是( )
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