一封英文信可以有多種主題和內容。以下是一封簡單的英文信的例子：
```
Dear Parents,
How is everything these days? I miss you very much. I am very happy at my new school. My teachers and students are very friendly to me. They often help me with my study. Now I am not worried about my English because I make a lot of progress in it and I become more and more interested in it. My school life here is also wonderful. I take part in many part-time activities and make many friends there and learn lots of learning methods. Now final exam is coming. I am busy preparing it. I will try my best to do well in it. I am glad that the summer holiday is coming. I want to take part in a Green City Group. I think I should make a contribution to protecting our environment. It's hot these days but I can take good care of myself.You should pay more attention to your health.
Best wishes to you. Love you,
Yours,
[Your Name]
```
這封信主要是表達對父母的思念，分享自己在學校的快樂生活，以及即將到來的暑假計劃。信中還包含了對父母健康的關心和祝福。這封信的內容豐富，情感真摯，適合與父母分享近況和學習生活。