A:was happening
B:to happe
C:has happened
D:had happened
我们还小,不用讲文明,懂礼仪。( )
下列对生命系统结构层次的说法正确的是( )
如图,由9个全等的等边三角形拼成一个几何图案,这个图案中共有平行四边形( )
I'm surprised to find that my shoes are ________ the same as Jim's.