2017年2月23日内容（周四）
Merriam-Webster’s Vocabulary Builder


词根: peri
词根释义：going around something
词根背景知识补充：这个词根简单例子比较少，periscope算是比较容易记忆的一个，我们说过scope表示“视野”，什么什么“镜”也老出现scope词根，比如telescope表示“望远镜”。所以periscope也是某镜，叫做潜望镜，戴上它可以see around corners。


1. perimeter [pə'rimitə]
定义: to boundary or distance around a body or figure
例句: All along the city’s perimeter the guerrillas kept up their attack night after night.
例句语法结构：主谓宾
例句中文翻译：游击队沿着城市周界日夜进攻。
单词中文意思及词性：perimeter n. 周长；周界
介绍段落精简句型解析及推荐背诵句式：The entire perimeter of Australia is bounded by water. 澳大利亚四周都是水。

2. periodontal [,periə'dɔntəl]
定义: surrounding the teeth
例句: Years of bad living had filled his teeth with cavities, but it was periodontal disease that finished them off.
例句语法结构：主谓宾，强调句
例句中文翻译：好几年不良生活导致他的牙齿都是蛀牙，但是牙周疾病彻底毁了他的牙齿。
单词中文意思及词性：periodontal adj. 牙周的
介绍段落精简句型解析及推荐背诵句式：periodontist，牙周病医生。简单说来，牙周病比较严重，因为有可能会hold不住牙齿在本来应该在的位置（they can no longer hold the teeth in place）。

3. peripatetic [,peripə'tetik]
定义: (1) having to do with walking; (2) moving or traveling from place to place
例句: She spent her early adult years as a peripatetic musician, traveling from one engagement to another.
例句语法结构：主谓宾，非谓语动词做伴随状语
例句中文翻译：她刚成年那几年，是个游历的音乐家，到处赶场。
单词中文意思及词性：peripatetic n. 走来走去的人；adj. 巡游的
介绍段落精简句型解析及推荐背诵句式：这个词其实是用来说哲学家亚里士多德的。peripatetic soul的状态就是wandering far and wide。但如今商界的“空中飞人”也可以用这个词：Today peripatetic executives and salespeople move from one job to the next and stare into laptop computers while flying from city to city. 你们觉不觉得stare into这里用的非常有画面感啊？（常见的“凝视”搭配是stare at sth.）

4. peripheral /pəˈrɪfərəl/
定义: (1) having to do with the outer edges, esp. of the field of vision; (2) auxiliary
例句: The teacher seems to have eyes in the back of her head, but what she really had was excellent peripheral vision and a thorough knowledge of how ten-year-olds behave.
例句语法结构：主谓宾，主系表
例句中文翻译：这老师就像脑袋背后长了眼睛一样，但她真正拥有的是周边视觉，以及对十岁左右的孩子们行为的透彻了解。
单词中文意思及词性：peripheral adj. 外围的；次要的 n. 外部设备
介绍段落精简句型解析及推荐背诵句式：比如老司机在开车的时候，周边视觉peripheral vision就很重要，尤其是在变道switch lanes的时候。