非常谢谢你的详细的解答。我儿子的CASE目前正在等待排期当中。是否转到了国际签证中心没有,我也不知道,也许还没有吧。我会按照您说的给移民局先写信。再次感谢您的帮助!
-Unless you receive a letter from USCIS that your I-130 case has been approved and transferred to NVC, your I-130 will still be in USCIS. So, send your letter to USCIS address indicated in your I-130 filing receipt.