Read the following paragraphs and cross out the irrelevant sente

Read the following paragraphs and cross out the irrelevant sentences.
The recent water shortage in California forced changes in Californian's lifestyles. When water was rationed, Californians learned to conserve water. They didn't water their lawns or gardens or wash their automobiles. They took fewer showers and baths. The water shortage lasted two years. Californians also learned to recycle water. For example, they used the rinse water from their washing machines to water their house plants and gardens.
【正确答案】：When water was rationed, Californians learned to conserve water.
【题目解析】：p139