（因）……，故…… for “Since …, Therefore …”
Read and write formal notices with （因）……，故……, where 故 means “therefore” and 因 means “because of”.
文型
（因 + cause），故 + result
故 is a very formal “therefore” that opens the result clause; 因 in front of the cause is optional. You meet it mostly in written notices, letters and reports.
因天气原因，故本次活动改到下周举行。
When to use （因）……，故…… for “Since …, Therefore …”
故 is a classical word for “therefore”. It begins the second clause and introduces the result or decision: ……，故…… “…, therefore …”. The first clause gives the reason and often begins with 因, a written form of 因为: 因天气原因，故本次活动改到下周举行 “Owing to the weather, this event has been moved to next week.” 因 is optional, which is why the outline writes it in brackets.
因报名人数已满，故不再接受报名。
As the places are all filled, no more sign-ups will be accepted.
因时间有限，故不能一一回答大家的问题。
As time is limited, we cannot answer everyone’s questions one by one.
他平时很少练习，故成绩一直不太理想。
He seldom practises, so his results have never been very good.
因图书馆周末要打扫，故暂停开放两天。
As the library is being cleaned at the weekend, it will be closed for two days.
よくある間違い
- 故 opens the result clause, never the reason clause: 因天气原因，故改期, not 故天气原因，因改期.
- Don’t use 故 in casual conversation; 所以 is the everyday word.
- 故 means “therefore”; 故意 means “on purpose”. Don’t mix them up.
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