色多多在线观看播放-色多多在线观看高清免费-色多多在线观看视频-色多多在线看-欧美aaaaa性bbbbb小妇-欧美aaaav免费大片

沒有過去就沒有未來。

Coal built the modern world, and it's our responsibility to ensure its legacy is managed with wisdom.

We don't inherit the land from our ancestors; we borrow it from our children.

科學精神是追求真理、實事求是的精神。