complexity : 着重指极度复杂而难于辨认的关系。
- a problem of great complexity
- the increasing complexity of modern telecommunication systems
- I was astonished by the size and complexity of the problem.
complication : 指纷乱复杂到令人难于理解的地步。
- Dave couldn't find his passport at the airport and then there were further complications when Fiona lost her baggage.
- If any complications arise, let me know and I'll help.