题目

完型填空。 Planting flowers is my favorite hobby because I can learn something new from it. I bought a flower pot (盆) and some flower seeds (种子) last week. Then I   1   some seeds in the pot. After a few days,   2   happened. But I didn’t give up watering（浇水）. Another ten days later, I saw the young plants   3  . I felt very   4   because I could grow something. Just like growing flowers, we can also plant happiness（快乐、幸福）. Our life is   5   an empty (空的) pot. We have lots of things to do, but we   6   do them. That means 已知向量，满足||＝，||＝3，与的夹角为45°，求|3－|的值．