1:Wang Bing,Lily and her sister are all at school.（all要放在be动词后）
2:The girl on the bike is my sister.(骑在自行车上固定的用介词on)
3:There are six butterflies in the photo.(butterfly 变成复数是butterflies)
4:Why do many students like doing in the summer?(在夏季是inthe summer )
5:Have you bbought your suitcase?(这是完成时,buy要用过去分词）