以免 + Verb Phrase
免 (miǎn) means "to avoid" or "to be exempt from" and is often used in the phrase 以免 (yǐmiǎn), meaning "so as to avoid" or "in order to prevent." This construction introduces a clause describing an undesirable outcome that the speaker wants to prevent.
出门前检查一下门窗,以免被人闯入。
chūmén qián jiǎnchá yīxià ménchuāng, yǐmiǎn bèi rén chuǎngrù.
Check the doors and windows before going out, so as to prevent break-ins.
你最好提前订票,以免到时候买不到。
nǐ zuìhǎo tíqián dìng piào, yǐmiǎn dào shíhòu mǎi bù dào.
You'd better book tickets in advance, so you don't end up unable to buy them.
多穿点衣服,以免着凉。
duō chuān diǎn yīfú, yǐmiǎn zháoliáng.
Wear more clothes so you don't catch a cold.