鸟类肢的发育主要靠（）。
A.细胞的程序性死亡
B.细胞增殖
C.细胞运动
D.细胞粘合
参考答案：A
The ____ look on her face suggested that she _____ such a result. [ ]
A. puzzling; hadn't expected
B. puzzled; hadn't expected
C. puzzling; wouldn't expect
D. puzzled; shouldn't expect
急性化脓性中耳炎可为麻疹、猩红热等急性传染病的并发症。
