Hundreds of years ago, no dandelions (蒲公英) grew in North America. Then people

　　came from Europe.They had dandelion seeds on their clothes. The seeds fell from their clothes onto the ground. Since then, dandelions have spread all over.

　　Most people believe that dandelions are weeds. They do not want them in their gardens. But some people think that dandelion flowers are pretty. And others think that dandelions taste good. They cook dandelion leaves or put them into a fresh salad. The leaves must be picked before the flowers come out or they will not taste good. Some people make dandelion flowers into wine.

　　Dandelions do not die easily. If the winter is not very cold, their leaves may stay green.

　　When the spring arrives, their flowers come out. Each night their bright yellow flowers close

　　up. When the sun shines the next day, they open up again. Dandelion flowers are very unusual. They do not have to get pollen (花粉) from another dandelion flower in order to form seeds. So after several days, the yellow flower turns white and soft. A tiny brown seed forms at the bottom of each white petal (花瓣). When the wind blows,  the petals float away.

　　Each white petal carries a seed away. This lets the dandelions spread their seeds all over.

　　New dandelions grow where the seeds land.

　　31. The underlined word “weeds” means       .

　　A. pretty flowers    B. fresh vegetables    C. wild plants    D. green trees

　　32. When is the best time to pick dandelion leaves to eat?

　　A. After their flowers come out.    B. After their flowers turn white.

　　C. Before their flowers come out.    D. Before their flowers close up.

　　33. What is the best title for this passage?

　　A. The History of Dandelions    B. Dandelions: Flowers or Food

　　C. The Use of Dandelions    D. How to Grow Dandelions