形容词 “complex”
 基本形式 complex (more/most)
- 复杂The human brain is a complex organ with many interconnected parts. 
- 复数的In our math class, we learned how to add and subtract complex numbers. 
名词 “complex”
- 综合体The new apartment complex has a gym, a pool, and a small park for residents. 
- 相互连接的系统Concerns about the growing power of the military-industrial complex have led to increased scrutiny and debate among policymakers and the public. 
- 情结His fear of abandonment is thought to stem from a complex developed in early childhood. 
- 配合物The biochemistry lecture covered how enzyme-substrate complexes are essential for metabolic reactions.