读报
登录注册网站首页
 

STEPPING UP

World’s deepest hole?

作者:TEENS
Aa
  • -   
  •    +

学语法

How long …

How far …

How deep can humans go into Earth? This is a challenge (挑战) for scientists around the world. To find the answer, scientists try to dig deep holes.

点击阅读全文
联系我们  |  诚聘英才  |  关于我们  |  版权声明
© i21st.cn   京ICP备2024066071号-1
 
选择报纸
选择报纸
关闭