"我们乘车去购物" 的英文表达可以是 "We are going shopping by car."

这句话的来源是英语中常用的表示出行方式的短语：

"by car" 表示乘车，例如：

"We are going to the beach by car." (我们乘车去海滩。)

"I usually go to work by car." (我通常乘车去上班。)

"by bus" 表示乘公共汽车，例如：

"She takes the bus to school every day." (她每天乘公共汽车去学校。)

"We are going to the museum by bus." (我们乘公共汽车去博物馆。)

"by train" 表示乘火车，例如：

"He travels by train every weekend." (他每周末都乘火车旅行。)

"We are going to the city by train." (我们乘火车去城市。)

"by plane" 表示乘飞机，例如：

"She is going on vacation by plane." (她乘飞机去度假。)

"We are going to Paris by plane." (我们乘飞机去巴黎。)

希望这些例句能帮到你。