My I-140 was approved 2 years ago and I-485 is still pending. My H-1b will be expired in November 14, 2007. My employer (university) told me the earliest date to an extension application for my H-1b is June. I plan to visit China between July 20 and August 30. I would like to know when is good time to file H-1b extension: before my travel to China or after I come back from China? I heard if I left the US after filing H-1b extension (it is pending), it means I give up the H-1b extension automatically and it will not be approved. Is it true? My current H-1b is multiple entrance until Nov. 14. If I use it to enter the US on August 30 which is close to expired date (2.5 months left), is it easy to enter the US or not? I have used 4 years H-1b, can I apply for 3 more years extension when apply for it? I greatly appreciate your help with these questions.