题目

众所周知，二氧化碳能使澄清的石灰水变浑浊（生成白色沉淀）．但是，在分组实验中，向石灰水中通入二氧化碳（如图1所示），出现了意想不到的现象：有的石灰水未变浑浊；有的出现浑浊后又变澄清（沉淀消失）． 【提出问题】分组实验中，出现意想不到现象的原因是什么呢？ （1） 【猜想与假设】 I．石灰水未变浑浊，是因为二氧化碳中混有少量氯化氢气体．Ⅱ．石灰水未变浑浊，是因为．Ⅲ．石灰水出现浑浊后又变澄清，与石灰水的My name is Li Ming. I’m a student   21  the No. 1 Middle School. There are many   22  in our school: the English Club, the Art Club, the Music Club   23  more. I’m in the Music Club.  24  have a talent (才艺) show at our school every   25 . The students from those different (不同的) clubs can   26  their talents. They can sing, dance and 27  pictures. They can   28  the guitar (吉他), the piano and the drums (鼓). We all like the   29  very much. This year I   30  to sing an English song at the show. I hope they’ll like my song.小题1:A．withB．ofC．forD．to小题2:A．studentsB．peopleC．clubsD．teachers小题3:A．butB．orC．andD．so小题4:A．WeB．YouC．TheyD．She小题5:A．dayB．weekC．monthD．year小题6:A．speakB．showC．findD．look小题7:A．takeB．buyC．drawD．watch小题8:A．makeB．playC．haveD．cut小题9:A．pictureB．footballC．schoolD．show小题10:A．want B．helpC．runD．let