Alongside是along沿着,<the boat docked alongside the pier>
也是beside在旁邊,<standing alongside me>
另外也可解作‘跟(某人)为伴’。<My wife and I are walking alongside each other through a forest trail>
Alongside强调接近,with则泛指在一起。比如说,We are eating alongside each other形容我们吃饭时坐得很近,可能是肩膀靠肩膀。We are eating with each other只是形容坐在一起,可能是同一桌子吃饭。