null pick-up

例句：

1. 1.The truck was empty when we arrived at the warehouse.
   我们到达仓库时，卡车是空的。
2. 2.They were waiting for a null pick-up from the airport.
   他们在机场等待一个空车来接他们。
3. 3. He decided to take a null pick-up and drive to the city.
   他决定坐空车去城里。