题目

对话填空，每空一词，词的第一个字母已经给出.     A: Hi, Mary. You look pretty h____1.___!   B: Thank you. I often  e___2.____. A: How o___3.___ do you do sports? B: About three t__4___ a day.   A: What about your food? B: I try to eat d __5___ kinds of vegetables and fruit. Also I d__6___ milk every day. But I n___7__ drink coffee. A: Then how m___8___hours do you sleep every night? B: Nine. I need lots of sleep. A: Oh I see.Your good h__9___help you keep in good h__10___. B: That’s right.从8名女生和4名男生中，抽取3名学生参加某档电视节目，如果按性别比例分层抽样，则不同的抽取方法数为( )A.224 B.112 C.56 D.28