好久不见了！Long time no see.
辛苦了！You've had a long day. You've had a long flight.
尊敬的朋友们！Distinguished/Honorable/Respected friends阁下（多用于称呼大使）Your Excellency
On behalf of the Beijing Municipal government, I wish to extend our warm welcome to the friends who have come to visit Beijing.
On behalf of the Beijing Municipal government, I wish to express our heartfelt thanks to you for your gracious assistance.
在北京过得怎么样？How are you making out in Beijing?
我一定向他转达您的问候和邀请。I'll surely remember you and your invitation to him.
欢迎美商来北京投资。American businessmen are welcome to make investment in Beijing.
欢迎多提宝贵意见。Your valuable advice is most welcome.
不虚此行！It's a rewarding trip!
您的日程很紧，我们的会见是否就到此为止。As you have a tight schedule, I will not take up more of your time.
请代我问候王先生。Please remember me to Mr.Wang.
感谢光临！Thank you so much for coming.
欢迎再来！Hope you'll come again.
欢迎以后多来北京！Hope you'll visit Beijing more often.
请留步，不用送了！I will see myself out, please.
祝您一路平安！Have a nice trip!