Maybe you have to put on a face.

也许你必须强颜欢笑。

I'm a teacher but sometimes I have to put on a face like, you know, a stricter teacher.

我是名老师，但有时我必须板起脸露出更严厉的一面。

I wanted to cry, but I just had to put on a face when I talked with the clients.

我很想哭，但与客户交谈时我只能强颜欢笑。

You had to put on a face, this implies that things are going poorly, but you have to pretend like everything's fine.

你必须装出一副样子，这意味着事情进展不顺利，但你必须假装一切都很好。

We got dressed up, we put on a face paint, we built sets, and then we brainstormed our stories by acting them out.

我们换上了戏服，脸上涂上油彩，做好了布景，边演边想我们的故事。

By the leaders of those two countries, Mexico's President Andres Manuel Lopez Obrador has been reluctant to put on a face mask to prevent the spread of the disease.

与这两个国家的领导人相同，墨西哥总统安德烈斯·曼努埃尔·洛佩斯·奥夫拉多尔一直不愿戴上口罩来防止疾病的传播。

Or we could cut out the word happy completely and just say, I had to put on a face in front of the clients, even though I had just gotten yelled at by my boss.

或者我们可以完全删掉“快乐”这个词，只说，我必须在客户面前强颜欢笑，尽管我刚刚被老板吼了。