在中文拼音里，u的拼写（Spelling rules of “u”） u自成音节时，要在前边加上w,在一个音节开头时，要写成w。例如:u→wu、uan→wan。 When“u” forms a.syllable by itself,it should be written as “wu”；when“u”occurs at the beginning of a syllable,it is written as “w”,e.g.“u”→“wu”,“uan”→“wan”.