剑桥词典a dot followed by three letters , such as .doc or .jpg, that forms the end of the name of a computer document （计算机）文件扩展名（． 后跟三个字母，如 ．doc 或 .jpg，形成的计算机文件扩展名） Be sure to type in the document name and file extension before you click "save ". 在点“保存”前要输入文件名和扩展名。 返回 file extension