in the 20th century,in the 1950s,这两个时间词的前面为什么要加 the?

in the 20th century是什么意思 a leading figure in the 20th century theater. meaning in the 16th century什么意思 Europe in the 18th century是什么意思 Realistic novel in the 18th century in 18th century 要不要加the变成in the 18th century life in the 21st century will be different from life in the 20th century是什么意思 英译中 in the 1950s in the 19th century 可以说in 20th century?in后必须加the吗? LOVE IN THE TIME OF CHOLERA PENGUIN GREAT BOOKS OF THE 20TH CENTURY怎么样 he was the youngest man to play for England in the 20th century. in the second half of the 19th century 20世纪初期可不可以说in the beginning of 20th centuryat the beginning of 20th century In the 20th century,there were many i_____ such as CDs and video games 填空 in the early part of the 19th century 和 at the beginning of the 19th century 的区别. in the 20th century,in the 1950s,这两个时间词的前面为什么要加 the? discuss the concept of wasteland in relation to the works of those writers in the 20th century American literature He was a fomous artist in _____. A the 19th Century B the 19 Century C 19 Century