HSK 7-9
以防
yǐfáng
In order to prevent; just in case
Structure
Action/Precaution + 以防 + Undesirable Situation
How it works
The conjunction '以防' (yǐfáng) is used to connect two clauses where the second clause describes a negative outcome or situation that the subject aims to avoid. It is frequently used in formal or written contexts, serving a similar purpose to '免得' (miǎnde) but carrying a more serious tone.
Examples
出门前请检查窗户是否关好，以防小偷进入。
Chūmén qián qǐng jiǎnchá chuānghu shìfǒu guānhǎo, yǐfáng xiǎotōu jìnrù.
Please check if the windows are closed before going out, to prevent thieves from entering.
即使是晴天，他也总是随身带一把伞，以防万一。
Jíshǐ shì qíngtiān, tā yě zǒngshì suíshēn dài yī bǎ sǎn, yǐfáng wànyī.
Even on sunny days, he always carries an umbrella just in case.
公司备份了所有重要数据，以防系统崩溃导致丢失。
Gōngsī bèifènle suǒyǒu zhòngyào shùjù, yǐfáng xìtǒng bēngkuì dǎozhì diūshī.
The company backed up all important data to prevent loss caused by a system crash.
Common mistakes
Confusing '以防' with '防止'. '防止' is a verb usually followed directly by a noun phrase, whereas '以防' is a conjunction linking two clauses or introducing a purpose.
Tip
Memorize the fixed idiom '以防万一' (yǐfáng wànyī), which means 'just in case.' It is the most common way to use this grammar point in daily conversation.
More HSK 7-9 grammar
See 以防 in real Chinese
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