科学家为了证明某一观点先后做了如下两个实验：（1）破坏蝌蚪的甲状腺，发现蝌蚪停止发育，不能发育为成蛙；（2）在饲养缸的水中放入甲状腺激素，破坏了甲状腺的蝌蚪又发育为成蛙．这两个实验可以证明（　　）

材料在人类生产、生活中有着重要的作用．下列有关材料的说法中正确的是（  ）

读课文《识字6》填一填。

____对丑，____对恨。____对虚假，____对热忱。____见真情，____献爱心

    Mr. White lives in the countryside with his wife, Mrs. White. From Monday to Friday he works in a small office near his house. He is free on Saturdays and Sundays. He has a nice garden near his house. He likes growing flowers and he usually works in the garden on Saturdays and Sundays. The flowers are colourful and beautiful. Mrs. White likes them very much. She often helps Mr. White. They live happily together.