Starting from version 2016, Office Simplified Chinese version is using DengXian (等线) as the default font for documents, not only for Chinese characters but also for Latin script. However, the DengXian font included in the Mac version of Office has a problem displaying the English apostrophe. There will be a large extra blank space after the apostrophe.
To reproduce this issue, just open Word (as an example, but this happens for all Office apps), type "It’s", and set the font to DengXian (等线). Note that the apostrophe should be the curly one _’_ , not the straight one _'_.
Office for Windows and Office for iPad do not have this issue. The apostrophe is displayed with DengXian font, without extra blank space. As a workaround, one can replace the DengXian font files (deng.ttf, dengb.ttf, dengl.ttf, version 1.13) included in Office for Mac with those included with Office for Windows (version 1.14), and after that apostrophe will be displayed correctly. But the font files will be overwritten again by Office updates.
Build number: Office for Mac 16.8 (171205), insider slow channel