complex adj. 复杂的，合成的，综合的 n. 联合体
例句：It's a complex question and your answer was too simple.
这是一个复杂的问题，你的回答来得太简单了。

complicated adj. 复杂的，难解的
例句：The tax laws are so complicated that only an expert can provide enlightenment.
税务法非常复杂，只有专家才能解释清楚。

complication n. 复杂化，（使复杂的）因素
例句：Lily's both parents work, which adds complications to their family life.
莉莉的父母都工作，这给他们的家庭生活增添了困难。

intricate adj. 复杂的，错综的，难以理解的
例句：The intricate machine requires a skilled operator.
这种复杂的机器须由技能熟练的人操作。

perplex v. 困惑
例句：When new math was introduced into schools, many parents were perplexed by it.
当学校开设新的数学课时，许多家长时此感到迷惑不解。