As we know，there     1 four seasons in China . It's    2   in spring（春）, hot in   3    , cool in autumn(秋) and cold in    4   . My   5  season is winter. Sometimes it snows（下雪）. Everything is all white. The world    6   clean and fresh(新鲜). I can go skating then.
    But Kitty likes summer    7  than winter. She says summer is   8     for sports. She can go  9   ,  sometimes in a lake and sometimes in a river. She   10 it very much .

某班第一小组6名女生在测仰卧起坐时，记录下她们的成绩（单位：个/分）：45，48，46，50，50，49．这组数据的平均数是（　　）.

下图所示的四个装置中,设计不合理的是 （   ）