Not sure about that. But my case is:
The consul canceled my previous valid B-2 visa. :(((((((((((
good luck anyway!
b*d 发帖数: 285
2
Those F visas are only valid for 6 months for Chinese. You can
enter USA twice before expired date. If your visa expired and
leave USA. it becomes nothing. Recommand you to try to get
F-1 visa from Canada.