【答案解析】Dear Sir or Madam,
I understand that your center is looking for a bilingual assistant working with foreign teenagers. I am writing to recommend Helen for this post.
Helen was my classmate at Beijing University. With her outstanding leadership and cheerful personality, she was elected chairperson of the Student Union several times. Since graduation she has been teaching bilingual lessons in an international high school for five years. She loves her job and enjoys working with children. This has made her popular among her students.
Therefore, I do not hesitate to recommend her as an ideal candidate for the post you advertised. I am sure you will make a wise decision in hiring her.