翻译：
76. 但是美国人看起来没有明白我们每天晚上需要7到9小时的睡眠。
77. Brady解释说脂肪细胞对缺乏睡眠有很大的反应。
78. 北极熊有厚的毛皮，大的脚掌，和其它一些特征使得它们能够为这种艰苦环境的生活做好准备。
79. 尽管这些北极熊是游泳能手，在水中它们比不上如闪电般迅速的海豹。
80. 它也是一个安全的方式，来让孩子们自己经历谎言失控时的情景。
81. I spent about two hours in reading and replying emails yesterday.
82. Do you know the man who gave a lecture yesterday?
83. She has already invited us to her birthday party.
84. I will call you the moment I get there.
85. She was promoted to the position of manager last year.