网友的句子，最后应该是个特殊疑问句，须加问号。

The warm weather outside may look perfect for outdoor exercise. But for those who are not that sporty, what could be nicer than having a relaxing afternoon tea with a few good friends and taking a break from studying?

【翻译】室外暖和的天气看起来很适合户外运动。但是对于那些不那么喜欢运动的人来说，还有什么比和几个好朋友喝一杯轻松的下午茶，以及离开学习休息一会儿更好呢？

我把这个特殊疑问句变成陈述句，有助于网友理解：

1. nothing could be nicer than having a relaxing afternoon tea with a few good friends and taking a break from studying.

2. 这个句子是个含有比较从句的复合句：

主句：nothing could be nicer

比较从句：than having a relaxing afternoon tea with a few good friends and taking a break from studying (could be)

3. 在比较从句中，两个并列的动名词短语作主语，后面省略了could be。

4. could 表示“推测”。