ài shēng tàn qì

唉声叹气 （唉聲嘆氣）

heave deep sighs of grief, anguish, worry, or frustration

moan and groan; sigh in despair

Example:

不要受了一点儿挫折就唉声叹气。
Bùyào shòu le yīdiǎnr cuòzhé jiù āishēngtànqì.
Don’t moan and groan because of a little setback.

她怎么整天唉声叹气, 愁眉苦脸的？
Tā zěnme zhěngtiān āishēngtànqì, chóu méi kǔ liǎn de？
Why is she looking so depressed and sighing all the time.