题目

的算术平方根是( )A. 7 B. C. ±7 D. ± 答案：【答案】B【解析】根据算术平方根的定义即可解答.解：∵，∴7的算术平方根是.故选B.Have you ever had problems in your life and don’t know how to be happy? If__1__，you will find“ Being a Happy Teenager” written by and Austrian writer Andrew Matthews useful． In this book，Matthews tells us how to have a happy life and__2__ the questions of teenagers．     There are many subjects，so stop being__3__and forgive．The book tells us some useful skills，such as how to put what you have learned into pictures of your mind to__4__ your memory better． Many teenagers think that happiness comes from a good exam result or praise from other people．But you call __5__ be happy when there are no such “good” things．Success comes __6__a good attitude（态度）．If you__7__problems，you will have success in the future． Some school students have problems，such as being too tall or short．But Matthews tells us that happiness comes from thinking about things __8__positive（积极的）way．If you are tall，people notice you and you can get a__9__view at the movie；if you are short，your clothes and shoes take less__10__ in your bedroom! This is Matthews’ most important lesson：you choose to be happy! （  ）1．A．so           B．not            C．this           D．that （  ）2．A．asks               B．answers        C．tells            D．says （  ）3．A．happy        B．excited        C．angry          D．relaxed （  ）4．A．make       B．let            C．change         D．use （  ）5．A．yet          B．already        C．still            D．too （  ）6．A．from       B．to           C．before         D．after （  ）7．A．hear from   B．learn from    C．come from   D．get in to （  ）8．A．at          B．in             C．on           D．with （  ）9．A．lower              B．worse         C．better         D．higher （  ）10．A．room      B．time           C．place        D．area