19. Great Depression 大萧条

从20世纪20年代末 （1929年） 持续到30年代早期的波及整个世界的经济萧条。

20. Thomas Edison [ `tRm[s ] [ `edisn ]

托马斯·爱迪生 (1847-1931)：美国发明家，获白炽灯、留声机、电影放映机等1093项发明专利，创办世界上第一个工业研究实验室（1876）。

21. Wright [ rait ] Brothers

[ 指Wilbur (1867-1912) 和 Orville (1871-1948) ] 赖特兄弟：美国飞机发明家，航空先驱，成功试飞（1903）第一架可操纵的动力飞机，开始了飞行器重于空气的时代。

22. at large

(1) 整体讲；大多数
People at large love peace and hate war.
The immigrants at large have contributed greatly to our country.
整体将移民对我国做出了重大贡献。

(2) 未被控制；自由自在
This disease is still at large.
I am sorry to say that the escaped murderer is still at large.

23. entertain [ 9ent[`tein ]

(1) vt. 娱乐；使……快乐
The boy entertained himself with a cartoon after finishing his homework.
The nursery teacher is entertaining the baby with building blocks.
幼儿园的阿姨正用积木给小儿逗乐。

(2) vt. 款待，招待
The hostess often entertains my friends over the weekend.
She was flattered by me and entertained me to lunch.
她受到了奉承，款待我午餐。

(3) vi. 请客；招待
She entertains a great deal.
她常请客。