a.酸性的；尖酸苛薄的 n.酸性

　　Acid rain is a result of air pollution.

　　酸雨是空气污染造成的。

　　When Mary criticized their work, you could feel the acid tone in her words.

　　玛丽在批评他们的工作时，你可以感觉出她话中那股酸溜溜的语气。

　　If we mix these two chemicals together, they will form an acid.

　　如果我们把这两种化学物混合在一起，他们会形成酸。

　　motivate

　　vt.促使，激发

　　Encouragement can often motivate students to study harder.

　　鼓励往往能激发学生更用功。

　　Peter is rude to girls. We should do something to motivate him to change his attitude.

　　彼得对女孩子很粗鲁。我们应有所作为以激使他改变态度。

　　motivation

　　n.动机；干劲

　　You should make sure that your motivation for losing weight is healthy.

　　你应该要确定你想要减肥的动机是健康的。

　　I have no motivation toward the project. I'm not interested in it.

　　我对这项企划没有动力。我对它不感兴趣。

　　pessimistic

　　a.悲观的（与介词 about 并用）

　　Paul is pessimistic about his future. He should learn to look on the bright side of life.

　　保罗对他前途持悲观的态度。他应学习看人生的光明面。

　　optimistic

　　a.乐观的（与介词 about 并用)

　　Investors are still relatively optimistic about the company's prospects.

　　投资人对该公司的前景仍旧相当乐观。

　　mist

　　n.薄雾

　　Because of the mist, we didn't have a clear view of the mountains.

　　我们因为雾气而看不清楚山景。

　　smog

　　n.烟雾

　　Los Angeles is known for its smog and its crime.

　　洛杉矶因烟雾与犯罪率而出名。

　　frost

　　n.霜

　　In the place where we live, you see frost on the ground in winter.

　　冬天时，我们住的地方地面都会结霜。

　　container

　　n.容器

　　You should store these cookies in a container with a tight lid.

　　你应该把这些饼干保存在一个有密闭盖子的容器里。

　　farewell

　　n.告别；送别

　　We said our last farewell to our good friend at her funeral.

　　我们在好友的丧礼中向她做最后一次的告别。

　　We threw a farewell party for David, who is retiring tomorrow.

　　我们为大卫举行惜别会，他明天就要退休了。

　　capitalism

　　n.资本主义

　　Many say that the U.S. is a country founded on capitalism.

　　许多人说美国这个国家是以资本主义立国。

　　capitalist

　　n.资本家

　　Mr. Tate was labeled (as) a capitalist at a young age, but his beliefs have changed since then.

　　泰特先生年轻时被视为是资本主义者，但之后他的想法改变了。