The document introduces the Chinese grammar structure "因為...而..." (yīnwèi...ér...) which is used to express cause and effect. It can be shortened to just "因". This structure is followed by the cause before "而" and the result after. Several examples are provided such as "因為生病而請假" which means "Because I got sick, I asked for time off". The document explains that this structure is used for more concise sentences in Chinese to connect a cause with its resulting effect.