久仰！ i've heard so much about you.
好久不見了！ long time no see.
辛苦了！ you've had a long 've had a long flight.
尊敬的'朋友們！ distinguished/honorable/respected friends
閣下(多用於稱呼大使) your excellency
我代表北京市政府歡迎各位朋友訪問北京。 on behalf of the beijing municipal government, i wish to extend our warm welcome to the friends who have come to visit beijing.
對您的大力協助，我謹代表北京市政府表示衷心的感謝。 on behalf of the beijing municipal government, i wish to express our heartfelt thanks to you for your gracious assistance.