有几题英语不会用适当的人称代词填空1.I own a blue bike.the red one does not be

有几题英语不会
用适当的人称代词填空
1.I own a blue bike.the red one does not belong to( )
2.LingLing is a girl .she studies in a primary school.her brother lives with()hleps()to prepare the lesson
3.you must look after ()things
4.we are in()room.()classroom is big
5.my sister is in ()room