How nice to hear from you again.
很高興再次收到你的回信。
Let me tell you something about the activity.
讓我告訴你一些關於這次活動的細節。
I’m glad to have received your letter of Apr. 9th.[/color]
很高興收到你在4月9號的來信。
I’m pleased to hear that you’re coming to China for a visit.
很高興得知你將來拜訪中國。
I’m writing to thank you for your help during my stay in America.
我正寫這封信感謝我在美國你對我的幫助。