complexus

例句：

1. 1. The problem is so complex that it's hard to solve.
   这个问题太复杂了，很难解决。
2. 2.The design of the new building is complex and requires careful consideration.
   新建筑的设计很复杂，需要仔细考虑。
3. 3. The complexity of the code makes it difficult for beginners to understand.
   代码的复杂性使得初学者难以理解。