-Yes, you can go any country and use AP to come back.
问题2,我现在有H1和AP,如果到第三国开会, 我应该继续申请H1吗(three more year)? 如果这样的话对原来的AP有什么影响?
-Up to you, but using AP is much more convenient. 继续申请H-1 is irrelevant to AP.
问题3, 如果直接使用AP, 对现在的H1有什么影响?
-After using AP, your status will be AOS, but you can continue to work for your current employer without EAD. You can reinstate your H-1b status by extenson, transfer or going outside U.S. to get an H-1 visa.