Most systems fall back to displaying a placeholder of some sort when an appropriate character can't be found in the current font.

当前字体中找不到某个适当的字符时，多数系统会显示一个某种占位符。

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Use no more than two different fonts — one for headings another for content and no less than a 30 pt font so that people at the back of the room can read them easily.

使用不超过两种以上的字体，一种是标题，另一种是正文，而且不要小于30号字，以便人们在背阴的房间中也能轻松阅读。

youdao

[font=Verdana]UNTIL recently, nuclear power seemed to be making its way back into public favour in Germany.

不久以前，核电在德国仿佛已重获公众的支持。

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One programmer has taken it upon himself to provide a fix for the change to bring the font size back to less-squinting normal.

FORBES: Is Facebook's New Font Size Too Small? Try Facebook Font Fixer

Like a nuclear missile silo, my agency's Vatican file had its own doomsday file - a hardbound manila folder on which a typewritten sticky label had emblazoned in telex font capitals: WHAT TO DO IN CASE THE POPE DIES. While many of the instructions dated back to 1961 and could be safely ignored, it was still an interesting study in panic.

CNN: Pope's resignation a new angle to a tough news beat