【单选题】根据以下材料,回答题 Better Solar Energy Systems: More Heat, More Light Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but__________ (51) now they haven't been very good...
【简答题】阅读下面短文,根据所给语境,按要求完成下列各题。 Failure is a part of life. No matter what we do, there are always two results:success and failure. There is no doubt that every one of us wants to be successful, but we can’t ...