阅读下文，完成下列各题。

        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？”答曰：“待君久不至，已去。”友人便怒：“非人哉！与人期行，相委而去。”元方曰：“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。

已知$\left|\overrightarrow{a}\right|=1,\left|\overrightarrow{b}\right|=3,<\overrightarrow{a},\overrightarrow{b}>={60}^{°},(\overrightarrow{a}-\overrightarrow{c})(\overrightarrow{b}-\overrightarrow{c})=0,$则$\left|\overrightarrow{c}\right|$的最小值是(     )

连词成句。

    Do you want to be happy? ____ They will help you become a happy person．

   ★Be thankful. There are so many things to be thankful for. ____ Thank your parents for preparing meals for you ; thank the school bus driver for driving you home safely and thank the mailman for bringing you your letters every day. By doing this you will feel happy．

   ★ ____ For example, read a good book , listen to your favorite music or spend time with your close friends. Don't spend too much time worrying about the future, such as going to college or getting a good job．

   ★ ____ You may forget about your trouble by joining in some activities like singing, dancing or swimming．★Help others. Many people feel happy after helping others ____ You can help a friend with his or her studies. You can read books for the children in your neighborhood. You can also be a volunteer to help the old or the disabled．