— Mom, I was the first to reach the top of the mountain.— Good job, Charlie. I'm ______ of you.
汽车清洗机是产生高压水冲洗车辆表面污垢的机器，其动力设备主要是电动机。如图中能说明电动机工作原理的是( )
In a few years' time, there _______ more trees on this hill.
