书籍 Four Corners 4 - 第 7 单元 D 课

at a time in the past, often used to introduce a fairy tale or fictional story

曾几何时

appearing mechanical or lacking emotion

机器人

a chair with wheels that is designed particularly for the use of disabled persons

轮椅

a state of being free from pain, worry, or other unpleasant feelings

安慰

very important or necessary for a particular purpose or situation

必不可少的

books, movies, etc. about imaginary things based on science

科幻小说

to have a real presence in the world, either physically or conceptually

存在

the latest or most advanced level of technology, design, or knowledge in a particular field

最先进的

an old person, especially someone who is retired

老年和退休公民

to guess the value, number, quantity, size, etc. of something without exact calculation

估计某事

to become less in amount, size, or degree

变得越来越少

all the individuals who work in a particular company, industry, country, etc.

劳动力

a state where there is not enough of something or someone

短缺

a period of time in which someone no longer works due to old age

退休期

a failure in the progress or effectiveness of a relationship or system

破坏事物的既定秩序

an order, particularly given by someone in a position of authority

（军事）命令

a way of communicating emotions or attitudes through movements and positions of the face, such as smiling, frowning, or raising eyebrows

表情

showing signs of future success or potential

有希望