3.第4句“最重要的原因是他們出于對(duì)安全的優(yōu)慮”直譯為T(mén)he most important reason is...，則主語(yǔ)較長(zhǎng)，為避免出現(xiàn)頭重腳輕的情況，可將safety concern用作句子主語(yǔ)，同時(shí)能起到強(qiáng)調(diào)作用。

　　4.最后一句中的“將自行車道及機(jī)動(dòng)車道分隔開(kāi)”補(bǔ)充說(shuō)明“標(biāo)識(shí)”的情況，可用現(xiàn)在分詞短語(yǔ)separating bicyclelanes from car lanes 來(lái)表達(dá)。

　　參考譯文

　　Most people agree that cycling is environmentallyfriendly and a good way to avoid traffic jams.However, they still have good reasons to abandoncycling. The most obvious one is the convenienceof the public transport, while safety concern is themost important reason. As bicycle lanes are oftenoccupied by cars, people have to risk their lives riding bicycles on motor lanes. Moreover, evenin some downtown areas, there are no clear signs separating bicycle lanes from car lanes.