Which statements of the following are true ones?

A.Since the spring of 1864, thousands of Chinese laborers had been shanghaied to San Francisco from China to construct the railway in US.

B.Chinese laborers　in US worked harder and faster and they got more pay.

C.Chinese laborers were more flexible in adapting to any natural or technical adversities.

D.The great contributions of over 14,000 Chinese laborers in US have been respected for ages.

正确答案：Since the spring of 1864, thousands of Chinese laborers had been shanghaied to San Francisco from China to construct the railway in US. ；Chinese laborers were more flexible in adapting to any natural or technical adversities.