闪光词汇及词组：
extensive: adj.广泛的
polish: v.使…更好
relevant industry:相关行业
spare time:空闲时间
ensure: v.保证
commitment: n.许诺
enclose: v.附寄
万能句型：
i am writing in response to your advertisement for…
the main reason for my confidence in this position lies in…
i have much spare time this semester, which can ensure my time commitment for the internship.
please find more details in my enclosed resume.
thank you for your time and patience, and i would greatly appreciate it if you could grant me an interview.