***在庆祝清华大学建校100周年大会上的讲话中指出：希望同学们要做到勤于学习、善于思考、勇于探索。以下对学习的认识正确的是（   ）
①学习是人类的基本活动，是人们生活的重要内容   
②考试焦虑是学习压力的一种表现，有利于我们在考试中取到好成绩
③我们在学习上要有求真的态度，讲究学习方法
④学习能使自己得到发展，能证明自身的价值，赢得尊重

小茜和胖胖体重分别为400N和700N，教学楼每层高度为3m，小茜从一楼上到五楼，胖胖从一楼上到三楼．则两人相比小茜克服重力做功较 ____

用课文原句填空。
①                            ,五十弦翻塞外声，沙场秋点兵。
②                            ，人不寐，将军白发征夫泪。
③更深月色半人家，                        。
④池上碧苔三四点，                        ，叶底黄鹂一两声，日长飞絮轻。
⑤过尽千帆皆不是，                         。

用方框中所给单词的适当形式填空，使短文通顺、正确、连贯（每个单词限用一次）。

      My grandfather is seventy years old, ____  he is still very healthy. He is tall and of medium ____ . He has short straight white ____ He likes reading. Every morning he ____  up very early and then reads morning ____ . When he reads, he always wears ____ . He also likes ____  chess, too. He always plays chess with his ____  friends. He ____  plays chess with me. Why? Because I ____ play chess.