[解析]
(1)D 推理判断题.根据文章第一段前两句"Scientists study the natural world by using"scientific method".When a scientist observes some phenomenon in nature,he develops an idea,called a theory or hypothesis (假设is ha."当一个科学家研究自然世界通过使用"科学方法"观察一些现象,他发展一个想法,称为理论或假说.故选D.
(2)A细节理解题.根据文章第二段的四个步骤"Step 1:Get an empty bottle with a small neck.A diameter (直径) of 1/2 inch should be ideal.步骤1:用一个小的颈部的一个空瓶子,直径(直径)1/2英寸应该是理想的.Step 2:Cut a sheet of paper to a square 5 inches on each si de.把一张纸剪成正方形,每英寸5英寸.Step 3:Crumple (压皱) the paper into a tight wad (块状物).步骤3:起皱(压皱)纸成紧(块状物).Step 4:Lay the bottle on its side and place the paper so it lies loosely in the neck of the bottle."步骤4:把瓶子放在旁边,把纸放在瓶子的颈部.可知不需要剪刀,故选A.
(3)D 主旨题.根据文章可知,这篇短文主要讲述了如何使用科学的方法做实验.注意常识符合题意.故选D.