回複：回複：急問：B1能在美國拿I-20轉成F1麽？還是得回國？

Not all the time. When enter with B1 it is not guaranteed you can change to F1 even if you have I20. You need to tell the custom officer that you intend to study and change to F1 when you enter the U.S. on a B1. Then the officer will make a notation on your visa page. Without that, you can't change to F1 when you are in the U.S.