【正确答案】Dear Frank,
First of all, I am glad to have received your e-mail! Thank you very much for your concern. I've been quite fine recently. And I went to the zoo on April 15^th with my parents. That day was my birthday. We had a very good time in the zoo. I took photos with many lovely animals, including the panda. I was really very happy. How have you been recently?

【答案解析】[写作点金]
电子邮件在写作文法上应注意以下几点：
1．切忌主客不分或模糊。例如：Deciding to rescind the earlier estimate, our report was updated to include$40，000 for new equipment.
应改为：Deciding to rescind our earlier estimate, we have updated our report to include $40,000 for new equipment.
2．句子不要零碎。例如：He decided not to audit the last ten contracts. Because of our previous objections about compliance.应该连在一起.
3．结构对称，令人容易理解。例如：The owner questioned the occupant's lease intentions and the fact that the contract had been altered with ink markings.
应改为：The owner questioned the occupant's lease intentions and ink alterations of the contract.
4．单复数不要搞乱，不然会看起来不舒服。
例如：An authorized person must show that they have security clearance.
所给范文结构清晰，用词简练，叙事清楚，并能够适当穿捅使用词组，值得借鉴。
[高频词句]
first of all首先
have a good time玩得愉快
look forward to...期待…