有研究者认为月球和地球可视为一个由两质点构成的双星系统，他们都围绕月球连线上某点O做匀速圆周运动．据此观点，若月球与地球的质量之比为1：80，则月球与地球绕O点运动的线速度大小之比υ₁：υ₂=______．

句子翻译。

1. In the afternoon, I'll show you around and_____________________(带你参观一些名胜古迹).

2. It would ____________(对我来说很重要) to listen to the tape and learn what is covered in the talk.

3. I'd like to tell you that our school ______________________(已经做出了一个新的规划).

4. In short, the students _________________(还没有达成一致).

5. In my opinion, Jiangcheng should______________________(科学地发展经济).