很想等一下被waitlist的学校，所以想向录取我的学校申请defer，大家看有希望吗？ 学校会给我保留一年学籍么？

Depends on which country. Usually Canadian schools are ok with deferring. But you need to talk to them first. Email, Phone calls. Whatever.... Phone call would be better. Try to talk to some international student director or similar person in the admission office.