Meaning of yuán yīn:
原因
cause; origin; root cause; reason; CL:個|个[ge4]
Tiānqì biàn lěng shì zhíwù bù zhǎng hǎo de zhǔyào yuányīn.
天气变冷是植物不长好的主要原因。
The cold weather is the main cause of the poor growth of the plants.
Tā bù zhīdào shìqíng de zhēnzhèng yuányīn.
他不知道事情的真正原因。
He doesn't know the true origin of the matter.
Tiānqì biànhuà shì shìgù de zhǔyào yuányīn.
天气变化是事故的主要原因。
The weather change is the main cause of the accident.
Tā chídào de yuányīn shì jiāotōng dǔsè.
他迟到的原因是交通堵塞。
The reason for his being late was traffic congestion.
Tā bù gàosu wǒ tā chídào de yuányīn.
他不告诉我他迟到的原因。
He didn't tell me the reason for his being late.