Re:

9月中旬已經遞交的EB1A的I-140和485，現在必須在下周回國，想取消I-485，要怎麽取消？會不會影響140的處理決定？

-You need to have the I-485 receipt to cancel the I-485. Just write a letter to USCIS to request the cancellation (enclose the I-485 receipt). By the way, I do not think you need to cancel the I-485. The denial of the i-485 will not affect your I-140 and that means your I-140 is valid as long as it is approved no matter whether the I-485 is denied or not.