统一是人心所向，大势所趋。维护统一、巩固统一始终是历史发展的主题。那些有利于国家统一的人或事在历史的长河中依然被后人传诵与铭记。

探究一：宝岛台湾在历史上经历了与祖国的三次分离。

探究二：当中国告别风云变幻的近代史时，也就告别了那个时代曾经的苦难。

探究三：早日完成祖国统一大业，是全体中华儿女的共同心愿。

下列现象中，机械能转化为内能的是（　　）

以色列为解决农业用水问题，实施的有效办法是（  ）

假定英语课上老师要求同桌之间交换修改作文，请你修改你同桌写的以下短文。短文中共有10处错误，每句中最多有两处。错误涉及一个单词的增加、删除或修改。

增加：在缺词处加一个漏字符号（∧）, 并在此符号下面写出该加的词。

删除：把多余的词用斜线（＼）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：每处错误及其修改均仅限一词

    On Wednesday of this Culture & Art Week, we invite the American teacher Prof. Hudson to our school. He gave a class to us and his class left us a very deeper impression.

    Prof. Hudson had a free talk with us in the simple but humorous English. He spoke slowly and clearly so that we could follow her well. In the same time, he would repeat that we did not understand.

Greatly encouraging, most of us took an active part his class.

    From his lessons, we came to the conclusion that it is not so difficult to learning English well.