That's a common custom in many families.

这是很多家庭的普遍习俗。

" Christmas stockings" is also a very common custom in the United States.

“圣诞袜”在美国也是很普遍的习俗。

But it's a common custom in U.S. restaurants, and you shouldn't be surprised by it.

但这是美国餐馆的普遍习俗，你不应该对此感到惊讶。

This is a common custom in many families, sometimes even when they eat in public at a restaurant.

这是许多家庭的普遍习俗，有时甚至在餐厅公开用餐时也是如此。

The common custom – the common practice is for students to sign each other's books, meaning they write their name and usually a short message to this student.

常见的习俗——常见的做法是让学生在彼此的书上签名，这意味着他们写下自己的名字， 通常还会给这个学生发一条短信。

China has developed an unique festive food culture throughout the years. Eating dumplings is a common folk custom for many Chinese on the day of winter solstice, especially those living in the north.

冬至经过数千年的发展，形成了独特的节令饮食文化，吃饺子则是多数中国人冬至的习俗。在北方尤其突显。

At Christmastime, for example, it's a common custom for children to go see Santa Claus and to sit on his lap – they sit on the top of his legs as he is sitting down.

例如，在圣诞节期间，孩子们去看圣诞老人并坐在他的腿上是一种普遍的习俗——当他坐下时， 他们坐在他的腿上。