脑死亡
参考答案：
脑死亡是指全脑功能不可逆地永久性停止。
腭裂发生于胚胎（）。
A.第3周
B.第6周
C.第7周
D.第8周
E.第9周以后
I call him ________, even there is not much to say.[ ]
A. now and then
B. by and by
C. step by step
D. more or less
