Black holes are not just cosmic vacuums; they are the ultimate laboratories for testing the limits of our physical theories.
劳动是一切财富和一切文化的源泉。
You are never too old to set another goal or to dream a new dream.
The whole of life is just like watching a film. Only it's as though you always get in ten minutes after the big picture has started, and no-one will tell you the plot, so you have to work it out all yourself from the clues.