Lucy says that each of them tries "to keep the sink, tub, and the toilet clean." The sink, "sink," is where you put the water - where you pour the water into in order to clean. A tub, "tub," sometimes called a bathtub, is a place where you put water. It's usually a long box in your bathroom that you put water into it and you then get into the water and you clean yourself, kind of like when you go swimming. You go in - your whole body goes into the water. Well, that's what a tub is, it's a large, long container that you put water into in order to take a bath. A toilet, "toilet," is what you use when you go to the bathroom, when you get rid of things out of your body.
n. 接收端,沟渠,污水槽,散热器
vi. 下