1. feeling blue: cảm thấy buồn

Ví dụ: She’s been feeling blue ever since her friend moved away.

2. go blue: cảm lạnh

Ví dụ: He tends to go blue when things don't go his way.

3. true blue: đáng tin cậy

Ví dụ: He’s a true blue friend who will always stand by you.

4. blue blood: dòng dõi quý tộc

Ví dụ: She comes from a blue blood family with a long history.

5. out of the blue: bất thình lình

Ví dụ: He called me out of the blue after years of no contact.

Đào Thị Cẩm Vân
Giáo viên tiếng Anh – Trường Quốc tế Á Châu