The example below is taken from Practical English Usage by Michael Swan.
(She was) talking to my husband, was she?
My question is the following:
Why is it "was she?" and not "wasn't she?"
Thank you.
" means the speaker is trying to determine if the woman mentioned was talking to the speaker's husband. This a straight determination-of-fact type of question. Nothing untoward would necessarily be implied here.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
"She was talking to my husband, wasn't she?" means the speaker is trying to determine if the woman mentioned was talking to the speaker's husband. This a straight determination-of-fact type of question. Nothing untoward would necessarily be implied here.
"She was talking to my husband, was she?" means the speaker is alarmed that the woman mentioned was talking to the speaker's hus
Both are possible. Typical contexts are:
"... wasn't she?" -- the speaker is expressing the suggestion or belief that she was, and is asking for confirmation.
"... was she?" -- the speaker is questioning what someone else has said or what seems to be implied by context, or, having more or less accepted its truth, is expressing disquiet or anger.