根据短文，选择合适的单词填入短文下面的横线中。

    It's spring now. The park is very beautiful. Look, the trees are green and the flowers are red. A bird is in the blue sky. Some ducks are in the big lake. There two boys in the small boat. They wear yellow shirts. One girl is painting the lake. What's in her? Oh, it's a rainbow. How it is!