回复：非常感谢您的解答。还有两个问题，看您能否再次帮助，谢谢！

use 1.
PRC passport holder MAY bypass the (lack of) Sino-US diplamatic reciprocal agreement and get multiple entry H1 visa stamp if he/she has Canadian PR, it will be up to US consular in Canada to decide.

Not good for 2. unless the US and China company are the same or parent-branch, and you did work for the Chinese one before.