by是什么時(shí)態(tài)的標(biāo)志詞

　　All the statistical computations were performed by the new software system.

　　所有的統(tǒng)計(jì)計(jì)算均由新的軟件系統(tǒng)完成。

　　They won by a single goal after extra time.

　　他們?cè)诩訒r(shí)賽中僅踢進(jìn)一球即獲勝。

　　They've increased the price by 50%.

　　他們已經(jīng)把價(jià)格提高了50%。

　　Now I can walk to work instead of going by car.

　　現(xiàn)在我可以步行去上班，而不必開車了。

　　I'm always broke by the end of the month.

　　我總是一到月底就沒錢花了。