回复：还有一个问题，从加拿大回来，拿哪个护照回美比较妥当呢？这次去加的时候肯定用中国护照。

Since your Canada passport will be stamped when exiting Canada, it would be good to use it to enter US so it would not cause issue when applying for citizenship.  Otherwise your passport will have only a pair of stamps of exiting/entering Canada but no other stamp which indicates you have other passport.