壮苗要有合理的()结构,叶面适中,才能获得稳产,高产。
A、个体
B、群体
C、单株
D、数量
参考答案：B
When he came back, he found the bag he had________over the seat was gone.[ ]
A. left to hang
B. left hanging
C. left hung
D. to leave hanging
中风的诱发因素主要有
A．烦劳
B．恼怒
C．醉饱无常
D．外感风寒
E．气候变化
leave hanging