A：牛顿发现了行星的运动规律
B：开普勒发现了万有引力定律
C：卡文迪许测出了万有引力常量
D：牛顿提出“日心说”
“他在位期间成功地完成了统一，结束了西晋末年以来近300年的分裂局面；他改革制度，注重吏治；他发展生产，减轻人民负担，使国家安定，经济繁荣。”这位皇帝应该是（ ）
End of Term Report
Student's name
Zhang Xing
Subject
English
Teacher
Mr. Dickens
At the beginning of this term
He found that studying English was very ____
In writing
His ____is better.
In speaking
He can have English ____with his friends and with me.
He can answer my questions in English____.
Next term
If he ____like this, he will do much better.
下列说法正确的是 （ ）
当你发现显微镜镜头不干净时，除去污物的正确方法是（ ）
