The pipes have oil or water, which is heated and sent to the storage tank until to produce electricity.
Operation rooms should be kept free ______ bacteria of any kind.
The League Secretary and monitor ______giving a speech while the rest of the class ________ listening attentively.
Mr. Wang is a man of _________ and we have got much _________ from him about how to make a living.
You can take ____ you like here.
It is said that his carelessness ____ the terrible accident.