Briefcases would be used as diaper bags.

公文包将被尿布代替。

We have quite an array of leather briefcases.

我们有相当的一批公文包。

Each carried a dark case, like big briefcases.

两人都提着一个像大公事包的黑箱子。

Do they hide their handbags or briefcases when they sit down?

当他们坐下来的时候会把他们的手袋或者公事包藏起来吗？

Then they produced sandwiches from their briefcases and started to eat.

然后他们就从他们的公文包当中拿出三明治开始吃。