Hi Karen, No.1 is good but for No.2 I have three changes to suggest. I would add the word "significant" or some similar word, and change "is" to "was" and also you don't need to say "my" college, only "college". "I found the most "significant" turning point in my life "was" when I stopped college." Hope this helps! Sinead

Karen, 你好. Your examples are good uses of “turning point,” but “is” should be “was” in the second example because you are talking about a turning point that happened in the past. Other examples: “The turning point in the football game occurred when the home team’s goalkeeper got injured. After that, the visiting team quickly scored three goals.” “The turning point in the war came when the invading army drove the government troops out of the capital city.”