c. 1400, from forward (adv.) + adverbial genitive -s. British English until mid-20c. preserved the distinction between forward and forwards, the latter expressing "a definite direction viewed in contrast with other directions." In American English, however, forward prevails in all senses since Webster (1832) damned forwards as "a corruption."
权威例句
1. Draw the floss backwards and forwards between the teeth.
将牙线在齿间来回拉动。
2. He controlled the car until it was pointing forwards again.
他稳住车子,直到它又朝前开去。
3. He stood a few moments, rocking back and forwards on his heels.
他站了一会儿,踮着脚跟前后摇晃。
4. Space scientists and astronomers have taken another step forwards.