一 We'll study in different schools next term. Enjoy your time in the new school.

— _______.

根据课文《钱学森》填空。

钱学森1934年毕业于____，随后____留学，师从____。他的愿望是：早日____，用____为祖国建设服务。1955年9月17日，钱学森终于踏上了____ 。他站在甲板上深情地____着远方，想到前方就是自己____的祖国，心潮澎湃。钱学森回国后，为我国____的研制和发射作出了卓越的贡献，被誉为“____”。

如图，∠ACB=90°，D为AB的中点，连接DC并延长到E，使CE=$\frac{1}{3}$CD，过点B作BF∥DE，与AE的延长线交于点F．若AB=6，则BF的长为（　　）

阅读短文，掌握大意，然后从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。

    A little sports shop is near my house. It sells (卖) many good things for  1 . At the shop, we can buy soccer balls,  2 , basketballs and so on. Today my  3 and I go to the4  to buy a tennis racket. There are a lot of 5 . And they have different  6   . I think every racket  7  very nice. My sister chooses (选择) a black one, because black is her favorite8  . You know, my sister is a big sports fan. She has a great sports    9   at home-five soccer balls, four basketballs and many tennis balls. She really likes   10  sports.

如图，已知l₁∥l₂∥l₃，DE=4，DF=6，那么下列结论正确的是（　　）