请好心人帮我写一篇80字的英语作文!急需!谢谢!

来源：百度知道 编辑：UC知道 时间：2024/05/21 10:56:46
写一封信。1．了解对方最近的学习情况。2．你的学习情况。3．请对方说说提高英语水平的经验。

Dear ***
We haven't met each other for a long time.Is everything going well with you?I have improved my way of study these days and I got a great mark in the latest exam.I feel very happy and I will make persistent efforts.
What about you?Have you made some achievements?I heard that your English is very well.Could you tell me some experience in English study?I will appreciate it very much if you tell me. I will wait for your letter.
Best wishes!
yours ***

染色体的主要成分是DNA(脱氧核糖核酸)和蛋白质.一个典型的染色体的基本形态有着丝点,次缢痕,随体.根据着丝点的位置不同,可把染色体分为四类:端着丝点染色体(长短臂的比值在7.0以上),近端着丝点染色体(长短臂的比值为3.0~7.0),亚中央着丝点染色体(长短臂的比值在1.7~3.0)和中央着丝点染色体(长短臂的比值为1.0~1.7).