在英语写作中，你需要在'mother-in-law'这样的复合词中使用连字符。

In English writing, you need to ___hyphenate compound words like 'mother-in-law'.

如果单词太长放不下，你可以在行末用连字符断开。

When a word is too long, you can ___hyphenate it at the end of the line.