2 sentences

1. 我从四五岁起就开始记事了。

   wǒ cóng sì wǔ suì qǐ jiù kāi​shǐ jì​shì le.

   I've been able to remember things since I was four or five years old.

   Source: Dong Chinese Dictionary

2. 他随身带着一个本子，方便随时记事。

   tā suí​shēn dài zhe yī gè běn​zi, fāng​biàn suí​shí jì​shì.

   He carries a notebook with him so he can jot things down at any time.

   Source: Dong Chinese Dictionary