"Wear a mask when you leave the house" 意思是出门佩戴好口罩。
这句话的来源可能源自于为了防止传染病的传播，提醒人们在出门时佩戴口罩。
一些英文例句和中文翻译如下：
"Remember to wear a mask when you leave the house to protect yourself and others." (记得出门佩戴口罩，以保护自己和他人。)
"It's important to wear a mask when you're in pubpc to reduce the spread of illness." (在公共场所佩戴口罩很重要，可以减少疾病的传播。)
"Don't forget to wear a mask when you go out. It's an easy way to help prevent the spread of disease." (出门时别忘了佩戴口罩。这是防止疾病传播的简单方法。)