词汇讲解：
1. fluent adj. (说话、写作等)流利的
例句：My father speaks fluent English.
我父亲讲一口流利的
英语。
2. infer vt. 推断, 推知, 推论, 猜想
例句：From his remarks, I inferred that he hadn't enjoyed his holiday.
从他的话中我推断他的假期过得不愉快。
3. frustrating adj. 产生挫折的；使人沮丧的，令人泄气的,令人懊恼的
例句：It was a demeaning and ultimately frustrating experience.
那是一次有失颜面并且令人沮丧至极的经历。
4. pharmacy n. 制药, 配方, 制药学
例句：Modern pharmacy has solved the problem of sleeplessness.
现代制
