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

Theorems are the milestones of mathematics.

If I'm honest I have to tell you I still read fairy-tales and I like them best of all.

Mental processes are means to ends in the struggle for existence.

The coal industry has been the backbone of America's energy independence for generations.

"There is no greater agony than bearing an untold story inside you."

We have a responsibility to future generations to leave the planet in better shape than we found it.