第四部分: 第一节: 根据首字母或汉语提示，在答题卷上写出完整的单词拼写（5分）

66. We should pay more attention to the healthy _____________ of children.(成长)

67. My father i_____________ on me the value of hard work.

68 Teachers should combine education with _____________(娱乐) ,which allows students to learn in a relaxing atmosphere.

69. Chemicals that are h_____________ to the environment are forbidden here.

70. Canada is a w________________ country in the world.

在刺激作用时间和强度-时间变化率固定不变的条件下，能引起组织细胞兴奋所需的最小刺激强度，达到这种强度的刺激称为（）。