What's the catch? 有什麼蹊蹺嗎?
You’re offering this for free? What’s the catch?
This deal sounds amazing, but what’s the catch?
Take/Make a Note/ Notes / (the note for)
take a note / make a note: 紀錄 n. 筆記 to take or make a note of sth. 記下某事物 to make a note to do sth. 記下要做某事 vt. 注意到; 注意 to note that ... 注意到… it is interesting to note that ... 有意思的是，… I'll just take a note of your name and address. 我記一下你的姓名和地址。 She made a mental note of the title. 她 牢牢地記住 了標題。 Make a note to call again next week.. 一定記得下週再打電話 He never takes notes in class . His new theory is worthy of note. This is the note for sth. 這是sth的筆記 Note it on your smartphone.