## 解决方案

Text-processing software typically assumes that an automatic line break may be inserted anywhere a space character occurs; a non-breaking space prevents this from happening (provided the software recognizes the character). For example, if the text “100 km” will not quite fit at the end of a line, the software may insert a line break between “100” and “km”. To avoid this undesirable behaviour, the editor may choose to use a non-breaking space between “100” and “km”. This guarantees that the text “100 km” will not be broken: if it does not fit at the end of a line it is moved in its entirety to the next line.