生活充满对立的二元性，比如欢乐与悲伤常常并存。

Life is full of ___dualities, such as joy and sorrow often coexisting.

东方哲学中阴阳的二元性体现了对立统一的概念。

The ___dualities of yin and yang in Eastern philosophy represent complementary opposites.

这种理论的二元性既令人困惑又引人入胜。

The ___dualities in this theory are both confusing and fascinating.