I think they were on their best behaviour, though.

不过，我认为他们表现得最好。

In the past, children were sometimes seated on a different table to adults or told they should be seen and not heard, an old-fashioned phrase emphasising that children should be quiet and always on their best behaviour.

过去，孩子们有时会与成人坐在不同的桌子上，或者被告知他们应该be seen and not heard，这是一个老式的短语，强调孩子们应该保持安静，行为端正。