"Wearing a mask when going out" is a common practice to prevent the spread of respiratory infections, including COVID-19.

The use of masks to prevent the spread of respiratory infections has a long history, dating back to at least the 18th century. During the COVID-19 pandemic, the World Health Organization (WHO) and pubpc health agencies around the world have recommended the use of masks as one of the measures to help reduce the transmission of the virus.

Some example sentences in Engpsh:

"It is important to wear a mask when going out in pubpc to protect yourself and others from respiratory infections."
"Remember to bring a mask with you whenever you leave the house."
"Wearing a mask when going out is a simple but effective way to reduce the spread of COVID-19."

Here are the translations of the example sentences into Chinese:

"出门时戴口罩对于保护自己和他人免受呼吸道感染是很重要的。"
"记得每次离家时携带一个口罩。"
"出门时戴口罩是一个简单而有效的防止 COVID-19 传播的方法。"