词义：nantian是一个中文词汇，意思是“难题、难以解决的问题”。

词性：nantian是一个名词。

词组搭配：常见的词组搭配有“难题重重”、“难过的天”。

短语：无

发音拼写：nn tin

五个中英例句：

1. 这个问题一直是个nantian，我们需要集思广益来解决它。　

This problem has always been a difficult one, and we need to brainstorm to solve it.

2. 我们正在努力克服这个困难，它是整个项目的nantian。　

We are working hard to overcome this difficulty, which is the nantian of the whole project.

3. 我的数学作业非常难，我不知道如何解决这个nantian。　

My math homework is very difficult and I don't know how to solve this nantian.

4. 这些年来我们一直在探索如何解决环境污染这个nantian。　

Over the years, we have been exploring how to solve the nantian of environmental pollution.

5. 生活中的各种困难都可以被视为是人生的nantian。　

All kinds of difficulties in life can be regarded as the nantian of life.

nntin

读音：nn tin

例句：

1. 这个公司的总部位于南天的城市。

Translation: The headquarters of this company are located in a city in the southern sky.

2. 南天是一个神秘而充满的地方。

Translation: The southern sky is a mysterious and tempting place.