第一题：Becasues she likes eating snacks very much

第二题：three 一共有3条建议，由first second third 可知

第三题： fruit,vegetables,grain,eggs,milk and meat

第四题：They won't become fat.They will be healthier.Students won't become tired at school,and they will have enough energy to study well.

第五题：It is delicious,but eating it often is bad for their health