When giving reasons in Mandarin Chinese, we use the word yīn wèi which means because.

The yīn wèi phrase explains the “why”, but the “what” must be explained with a second phrase which begins with suǒ yǐ (therefore).

The order of these two phrases is fixed: The yīn wèi phrase comes first and the suǒ yǐ comes second.
Chinese Characters

The Chinese characters of these two words are as follows:

    yīn wèi
    因為 (traditional)
    因为 (simplified)

    suǒ yǐ
    所以

Examples of Because … Therefore

    Yīnwei tā shēngbìng suǒyǐ méiyǒu lái shàngxué.
    She is sick, so she didn’t come to school.
    因為她生病所以沒有來上學｡ (trad)
    因为她生病所以没有来上学｡ (simp)

    Yīnwei wǒde qián bùgòu suǒyǐ méiyǒu mǎi.
    I didn’t have enough money so I didn’t buy it.
    因為我的錢不夠 所以沒有買｡ (trad)
    因为我的钱不够 所以没有买｡ (simp)

    Yīnwei xià dà xuě suǒyǐ fēijī tíng fēi.
    Because of the big snow, the flight was cancelled.
    因為下大雪所以飛機停飛｡ (trad)
    因为下大雪所以飞机停飞｡ (simp)