Annie wasn’t at school today because she had to stay at home to ________ her mother.

A．look after

B．look at

C．look up

D．look for

患铁缺乏症的因素包括（）

A.多次妊娠

B.妇女月经过多

C.多次哺乳

D.青少年偏食

E.婴幼儿辅食添加不足