1过去式：knew
过去式题目：
1. If I _knew_(know), I would say. 如果我知道，我就说了。
2. They bumped her off because she _knew_(know) too much. 因为她知道太多，所以他们把她干掉了。
3. This is because we _knew_(know) it all along. 这是因为我们一直知道这个事实。
4. She _knew_ (know) he loved her. 她知道他在爱她。
2过去分词：known
过去分词题目：
1. If I had _known_ (know) her intention, what happened later would have been different. 假如我知道她有这样的打算，也许后面的事情就不会发生。
2. But to me it was the end of the world, as I had _known_(know) it. 尽管我早已经知道，但这对我来说就是世界末日。
3. If I had _known_(know) it all at age 22, I probably would have been a little cocky. 如果我在22岁的时候就能知道这些了，我可能会变得有些骄傲自大。
4. Some parents said local officials had _known_(know) for years that the school was unsafe but refused to take action. 有些家长说，当地政府在几年之前就知道这所学校不安全，但没有采取任何措施。
5. This article identifies three natural methods I wish I had _known_(know) 30 years ago. 本文明确提出三个我希望自己在30年前就应该知道的方法。
