at cross purposes
Tom's parents acted at cross purposes in advising him;
his father wanted him to become a doctor,
and his mother wanted him to become a minister.
at death's door
He seemed to be at death's door from his illness.
at each other's throat
Mary and Harry have been at each other's throat so long that they have forgot how much they used to love each other.
at (one's) ease
One can never feel at ease with a toothache.
We put the child at her ease during the thunderstorm by reading her stories.
The sergeant gave his men the command "At ease."
at every turn
Because of his drinking, the man was refused a job at every turn.
at face value
This store's advertisements are honest; take them at face value.
at fault
The driver who didn't stop at the red light was at fault in this accident.
at first
The driver didn't see the danger at first.
at first blush
At the first blush the offer looked good,
but when we studied it ,
we found things we couldn't accept.