根据汉语意思完成句子。 1. Li Ping五岁时开始学习弹钢琴. Li Ping started to learn to play _____ the _____ _____ piano the five. 2. 从星期一至星期五,我们一上五天学. From _____ to _____ , we go to school five days a week. 3. 他性格外向,篮球打得也很好. He is _____ and _____ at _____ basketball. 4. -六下午你要干什么? -没什么要紧的事.你呢? — What are you doing Saturday afternoon? — Nothing serious. _____ _____ ______ ? 5. -我们一块做水果沙拉吧. -好主意.可是我们没有酸奶呀? — Let's _____ _____ _____together. — Good idea. But we haven't got any yogurt. 6. 夏季常食元葱对身体健康有好处. In summer, _____ good for health _____ _____onions often. 7. 包括班长,我们十五名同学参加了昨天的比赛. Including our_____ , fifteen students in our class _____ _____  in yesterday's competition.