第三部分 写作（共三节，满分55分）
第一节单词拼写（共10小题；每小题1分，满分10分）
根据下列句子及所给汉语注释，在横线上写出空缺处各单词的正确形式。
66. His English vocabulary is __________ (有限), because he pays little attention to it.
67. Your letter brought back many sweet ________ (回忆).
68. Scientists are researching into when the ________(宇宙) came into being.
69. ____________(准备) must be made for the coming grand ceremony.
70. He said he’d never been there, but he was __________ (撒谎).
71. __________ (三月) is my favorite month because spring is coming.
72.If you want to go abroad, you have to receive _________(身体) and mental tests.
73.He was _______(选择) as captain for his rich experience.
74. It is many years since I _______(吸烟).
75.If we had ________(驾驶) the car by turns, you wouldn’t have been so tired.
1）请你说说我国居民恩格尔系数下降体现了什么经济学道理，并简要说说下降的原因？（8分）
的单调减区间是 ．
，则
；
分别是
的中点，则
的大小等于异面直线
与
所成角的大小；
是四面体
外接球的球心，则
上的射影为
的外心；