交485时孩子到21 岁了，无法跟我们一起申请绿卡了。
1）现在孩子要去加拿大读硕士，我（绿卡付申请人）想到加拿大照顾孩子。是否有什么合法的方式离开美国比较长的时间，同时保留绿卡身份？
-You need to apply for reentry permit (RP) to stay in Canada, which allows you stay in Canada for > one year < two years. You can come back to US to re-apply for it before the old RP expires. You can leave US after you conduct the fingerprinting, not need to wait for the RP approval.
2）小孩硕士毕业自己申请485是否会比父母给申请快一些？小孩是加拿大出生，加籍
-You do both ways.
谢谢
