Cause Prepositions: 由于 & 因为
介词：由于、因为
Use 由于 and 因为 to introduce the cause or reason for a situation
Place 由于 or 因为 before the reason clause. The result clause may optionally include 所以. 由于 is more formal and often used in written Chinese; 因为 is versatile and used in both spoken and written contexts.
由于 focuses on objective causes and is rarely used in casual conversation. 因为 is the all-purpose "because" that works everywhere. When used as prepositions (before a noun phrase rather than a full clause), both introduce the cause directly: 由于天气原因 (due to weather reasons).
Lesson Targets
Podcast
Podcast: Cause Prepositions: 由于 & 因为 (介词：由于、因为)
Listen to Jason & Amy explain the 介词：由于、因为 pattern
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Understanding 介词：由于、因为
Both 由于 (yóuyú) and 因为 (yīnwèi) introduce the reason or cause for something, but they differ in tone and usage. 因为 is the everyday "because" — you can use it in conversation, writing, texts, and emails without thinking twice. 由于 is its more formal cousin, typically found in news reports, academic writing, and official announcements. When you hear 由于各种原因 (due to various reasons), you know the speaker is being formal or diplomatic. A key grammatical difference: 由于 tends to appear at the beginning of a sentence and works well as a preposition before a noun phrase (由于天气, 由于时间), while 因为 is more flexible and can appear in the middle of a sentence too (我没去，因为下雨了). For HSK 3, mastering both gives you the ability to express cause and effect in any register.
Key Points
- 因为 (yīnwèi) = "because" — all-purpose, spoken and written.
- 由于 (yóuyú) = "due to / owing to" — formal, mostly written.
- 因为 can appear at the beginning or middle of a sentence.
- 由于 typically appears at the beginning of a sentence.
- Both can pair with 所以 in the result clause, but it is optional.
- 由于 works well before noun phrases: 由于天气原因, 由于工作需要.
- 因为 is more personal; 由于 is more objective and impersonal.
In Chinese business and government communication, 由于 is preferred because it sounds objective and avoids assigning personal blame. Saying 由于各种原因 (due to various reasons) is a diplomatic way to explain setbacks without pointing fingers — a skill highly valued in Chinese professional culture.
Key Vocabulary
Example Sentences
由于各种原因，大家没有接受他的意见。
Due to various reasons, everyone did not accept his opinion.
他因为这件事一直不跟我说话。
He has not been speaking to me because of this matter.
由于天气不好，航班取消了。
Due to bad weather, the flight was cancelled.
因为堵车，我迟到了半个小时。
Because of traffic, I was half an hour late.
由于时间有限，我们只能讨论三个问题。
Due to limited time, we can only discuss three questions.
我没去参加聚会，因为身体不舒服。
I didn't go to the party because I wasn't feeling well.
因为 in the middle of a sentence
由于经济发展很快，人们的生活水平提高了。
Due to rapid economic development, people's living standards have improved.
Common Mistakes
由于 is used for objective, impersonal reasons. Personal feelings like "I don't like him" should use 因为.
For formal announcements with noun-phrase reasons like 天气原因, 由于 is more appropriate than 因为. Also, add 了 to indicate the completed action.
Practice Exercises
Tips & Tricks
Default to 因为 in conversation — it always works. Save 由于 for formal writing and announcements.
Quick rule: if you would say "due to" in English, use 由于. If you would say "because," use 因为.
In formal writing, 由于 + noun phrase is very elegant: 由于时间关系 (due to time constraints).
Remember that 因为 can go in the middle of a sentence, but 由于 almost always goes at the beginning.
Homework
Write four sentences using 因为 about everyday personal reasons (being late, missing class, etc.) and four sentences using 由于 about formal or objective reasons (weather, policy changes, economic factors).