Last summer, my family and I went on a camping trip in the mountains. We set up our tent by a small river, and everything seemed perfect. My little sister, Lily, was so excited that she immediately ran to the water to skip stones. A few minutes later, we heard her screaming from the riverbank. My dad and I rushed over to find out what happened. It turned out that she had slipped on a rock and fell into the water! Fortunately, she was okay, just a little shaken up. After we helped her out, we all sat around the campfire, laughing at how dramatic she was being.
In telling my story, the verbs in the first two sentences are in past tense. The third sentence shifts into present tense, and the fourth sentence starts out in past tense and then shifts to present tense. These unnecessary tense shifts can confuse the reader, so it's important to keep the tenses consistent. In this case, the story would flow better if all the verbs were in past tense.