be on the horns of a dilemma
US /bi ɑn ðə hɔrnz əv ə dɪˈlɛmə/
UK /bi ɑn ðə hɔrnz əv ə dɪˈlɛmə/

1.
进退两难, 左右为难
to be in a situation in which you have to make a choice between two things, both of which are unpleasant or difficult
:
•
She found herself on the horns of a dilemma: either she missed her flight or she missed her sister's wedding.
她发现自己进退两难:要么错过航班,要么错过妹妹的婚礼。
•
The government was on the horns of a dilemma, facing public outcry no matter which decision it made.
政府进退两难,无论做出何种决定都将面临公众的强烈抗议。