求翻译：当你收到信，或许我离开我的城市，去北京讲学大约一个月左右，我是兼职讲CAD 和3D课程（装潢设计专业）。我必须快乐和学生们一起，认真完成我的职责。是什么意思？

When you receive a letter, perhaps I left my city, go to Beijing to give lectures about a month or so, I am a part-time speaking cad and 3d courses (decoration design professionals). I must be happy, and conscientiously fulfill my duties with students.

When you receipt of the letter, and perhaps I have to leave the city I went to Beijing, lectured about a month or so, I am a part-time and 3 D CAD speaking course (decorating design professional). I must be happy and their students, careful my duties.

When you receive the letter, perhaps I leave my city, goes to Beijing to lecture an about for month, I am hold concurrent jobs to speak CAD and the 3D curriculum (decoration design specialized).I must joyful and the students together, earnestly complete my responsibility.

When you receive a letter, perhaps I should leave my city, go to Beijing to give lectures about a month or so, I am a part-time jobs about CAD and 3D courses (decorating design). I must be happy with the students, and earnestly fulfill my duties.

正在翻译，请等待...