函数y=的自变量x的取值范围是____ 。

   I like my bike. It brings me a lot of fun. When I was an1boy, my father bought it for me. It is my “horse”. I often go to school2 my bike. I like riding a bike 3 it is very convenient. If I go out by bike, it is 4 to find a place for parking it. Bikes are very cheap, so most people can buy one. There are three people in my family. 5of us has a bike. My parents are teachers in my school. In the morning, Mum, Dad and I each 6 to school. However on a rainy day we walk to school, because the road is bad for riding. I think riding bikes can make us7 . It not only helps us exercise more but also 8 the air clean. The bike is very important in Chinese people’s life. So riding bikes can help you to 9 more about China and the Chinese people. Now people in the world say China is the country of bikes because there are 10 bikes in China. I hope people all round the world like them.

We can hardly tell what life without the Internet will be like in the future, _________?

    【甲】陈太丘与友期行。期日中，过中不至，太丘舍去，去后乃至。元方时年七岁，门外戏。客问元方：“尊君在不？”答日：“待君久不至，已去。”友人便怒：“非人哉！与人期行，相委而去。”元方日：“君与家君期日中。日中不至，则是无信；对子骂父，则是无礼。”友人惭，下车引之。元方入门不顾。

    【乙】昔吴起①出，遇敌人而止之食。故人日：“诺，期返而食。”起曰：“待公而食。”故人至暮不来，起不食待之之。明日早，令人求故人。故人来，方与之食。起之不食以俟②者，恐其自食其言也。其为信若此宜其能服三军欤③欲服三军非信不可也！

【注释】①吴起：战国时著名的军事家。⑦俟：等待。③欤（yú）：句束语气词。