— Jim's mother dislikes cartoons in the Past, but now she likes to watch them with little Jim.

— Oh, just as the saying goes,         .

在一个不透明的口袋里装有仅颜色不同的黑、白两种颜色的球20只，某学习小组做摸球实验．将球搅匀后从中随机摸出一个球，记下颜色，再把它放回袋中，不断重复，下表是活动进行中记下的一组数据

（1）请你估计，当n很大时，摸到白球的频率将会接近____ （精确到0.1）．

（2）假如你去摸一次，你摸到白球的概率是____ ，摸到黑球的概率是____ 

（3）试估算口袋中黑、白两种颜色的球有____ 只．

    I remember believing in Santa when I was a very young girl. However, as I grew older, I learned many 1 that “proved” his nonexistence. Always 2 by nature, I was determined to use 3 to decide whether Santa Claus was 4

    The first year of tests5 when I was 5. I decided that if I 6 all night on Christmas Eve, I could see if Santa really came down the chimney. 7,that was a useless 8. I fell asleep that year, and when I woke up, I saw a 9wrapped present under the10.

    At age 7, I came up with another test to see if Santa was real. That year, I didn't send out my Christmas letter to Santa because I wanted 11 for Christmas, but this turned into a plot. By then, I 12 knew Santa wasn't real, but I wanted enough 13 to support this. That year was 14, because on Christmas Eve, my mother dragged me to our local Wal-Mart and led me around the toy section. I 15 to say a word, but did let my eyes 16 on a ballet set. I 17 that “Santa” wouldn't know what I wanted because he shouldn't be able to read my 18. However, mother would know everything that caught my eyes in the store. If I got the ballet set the next morning, I would have my evidence. Christmas morning, there was the ballet set, sitting under the tree again. 19 I didn't use it much, mother ended up returning it a few days later. She 20 Santa was generous enough to leave a receipt. That was the end to my task to discover the existence of Santa.

长期使用某种抗菌素，发现抗菌素的效果越越差．从达尔文的进化观点来看，这是由于（　　）