"He was seen while selling my phone."

[anton_t13]

Now "Anh ấy đã ĐƯỢCnhìn thấy trong khi đang bán cái điện thoại của tôi." wasn't accepted.
I already understand that "bị" and "được" aren't interchangeable. But what's the rule?

[SmartLatios]

"bị" is for something negative
"được" is for something positive

[tue145200]

Gét DUOLINGO

[Songve]

Do you mean ghét

[kn_lingo]

He WAS seen - I thought 'da' indicates past tense. However, one of the answers do not use 'da'.

[Thomas457134]

So why is "bi" included here?

[Songve]

bị is negative. This guy a pick pocket so the passive is negative here rather than được that is positive.

[Thomas457134]

So why is "bi" included here? It seems that it changes seen to seeing?