There is a new park near my house. My family often go to the park on the weekend. There aren't any tall buildings in the park. There is a big lake in the park. But we can't swim in the lake. There are many flowers and trees near the lake. There is a small hill behind the lake. Beside the lake, there is a small shop (商店). The park is beautiful. I like it very much.

一套故事书原价打八折后，用24.8元买回．这套书原价____元．

一个池塘被农药污染，在池塘中有一个食物链：浮游植物→水蚤→鱼→鱼鹰，则体内农药含量最多的生物是（  ）