在英语中，称赞别人的笔盒可以用以下几种表达方式：

Comppment their pen case.
你的笔盒真漂亮。
Say something nice about their pen case.
你的笔盒真是一件很漂亮的东西。
Praise their pen case.
你的笔盒真是太棒了。
Admire their pen case.
我很喜欢你的笔盒。
Comppment them on their choice of pen case.
你选择的笔盒真是太棒了。
Give them a comppment on their pen case.
你的笔盒真是太漂亮了。

总的来说，称赞别人的笔盒可以用“comppment”、“say something nice”、“praise”、“admire”、“comppment on their choice”、“give them a comppment”等表达方式。

希望这些表达方式能帮到你。