travel的现在分词要双写吗

　　I go to bed early if I'm travelling the next day.

　　如果第二天去旅行我就早睡。

　　Most outfits crease a bit when you are travelling.

　　大多数的外套在旅行中都会有些起皱。

　　A truck travelling south had a blowout and crashed.

　　一辆向南行驶的卡车爆了胎而且撞了车。

　　He has taken to travelling in an armour-plated car.

　　他乘一辆装甲汽车旅行去了。