以 yǐ

可以 kěyǐ — can 所以 suǒyǐ — therefore 以为 yǐwéi — to think (wrongly) 以前 yǐqián — before 以后 yǐhòu — after 以及 yǐ jí — as well as 以来 yǐ lái — since (a previous event) 全力以赴 quán lì yǐ fù — do at all costs 以便 yǐ biàn — so that 以免 yǐ miǎn — in order to avoid 以往 yǐ wǎng — in the past 以至 yǐ zhì — down to