Years ago, I lived in a building in a large city. The building next to ours was only a few feet away from mine. There was a woman who lived there and whom I had never met, yet I could see her seated by her window each afternoon, sewing   and reading. After several months had gone by, I began to notice that her window was dirty. Everything was unclear through the dirty window. I would say to myself, "Why doesn't that woman clean her window? It really looks terrible." One bright morning I decided to clean my apartment, including cleaning the window. Late in the afternoon I finished the cleaning, I sat down by the window with a cup of coffee for a rest. What a surprise! Across the way, the woman sitting by her window was clearly seen. Her window was clean! Then _ . I had been criticizing her dirty window, but all the time I was watching hers through my own dirty window. That was quite an important lesson for me. How often had I looked at and criticized others through the dirty window of my heart, through my own shortcomings   ? From then on, whenever I want to judge   someone, I ask myself first, "Am I looking at him through my own dirty window? " Then I try to clean the window of my own world so that I can see others' world more clearly. From the passage we can learn that   _   .
one shouldn't criticize others very often one should often keep his windows clean one should judge himself before he judges others one should look at others through his dirty window