地方性克汀病是由于（）

A.婴儿期摄入氟过多所致

B.母体妊娠期间摄入过多非必需微量元素所致

C.胚胎期和婴儿期碘摄入过多所致

D.胚胎发育期和婴儿期严重缺碘所致

E.胚胎期和婴儿期多种微量元素严重缺乏所致

句型转换。

1. He has to help his parents at home on Saturday.（改为一般疑问句）  

_______ he________to help his parents a home on Saturday?

2. I can play soccer at 5:00 pm.（对画线部分提问）  

_______ _______ _______play soccer?

3.I'm going to see the doctor with my friends this weekend.（对画线部分提问）  

_______ _______  _______ _______ with your friends this weekend?