There are four seasons in a year in Canada. They are spring, summer, autumn and winter. In spring, the weather is warm and sunny. I like to fly kites. In summer, it's hot. I like to swim. I often wear a pair of glasses and a hat. In autumn, it's always cool. I like to go to the park and ride down the street with my friends. In winter, it's cold and snowy. I like to go outside to skate and ski with my friends. Sometimes we make a big snowman, and then we dance and sing around it.

9　12　10　20　19　15　17

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地球表面两地,甲在东经120º,北纬4º;乙地在东经115º,北纬28º,则乙地位于甲地的（  ）

下列哪一组说法是正确的（　　）

①玉米种子的胚由胚芽、胚轴、胚根、子叶四个部分组成

②胚是种子的主要部分，是新植物体的幼体

③将一粒玉米种子纵切后，在切面滴碘液，整个切面都变得一样蓝

④种子中子叶发育为叶，芽发育为芽，胚轴发育为茎，胚根发育为根．