Retain newline. A non-negative size argument limits the maximum number of bytes to return (an incompleteline may be returned then). Return an empty string at EOF.
读取文件的一行，保留换行符，到文件末尾返回空串。
2
In terms of the standard sort of tree diagram of XML with the root element at the top, the incomplete elements will always be in the line down the right side of the tree.
如果从根元素在顶端的标准xml树关系图的角度来看，不完整的元素将始终位于该树右侧的直线中。
3
On the back of the bookmark I had written a line from Philip Larkin - "outside, the wind's incomplete unrest."..