Giải thích rõ nha Choose the letter A, B, C or D to complete the passage below Jeans are very popular with young people all over the world. Some people say that jeans are the "uniform" of youth, but they haven't always been (36) _________. The story of jeans started almost two hundred years ago. People in Genoa, Italy made pants. The clothes made in Genoa (37) _________called " jeanos". The pants were called "jeans". In 1850, a salesman in California began selling pants made (38) _________canvas. His name was Levi Strauss. Because they were so strong, "Levi's pants became popular with gold miners, farmers and cowboys. Six year later, Levis began making his pants with blue cotton cloth from denim. Soon after, factory workers (39) _________ the United States and Europe began (40) _________ jeans. Young people usually didn't wear them. Question 36: A. usual B. unique C. traditional D. popular Question 37: A. are B. were C. is D. was Question 38: A. of B. with C. from D. to Question 39:A. on B. in C. at D. from Question 40: A. wear B. wore C. wears D. to wear