to count on the fingers of one hand

(figuratively) to put one's finger on the problem, to put one's finger on it

around the clock, day and night, all the time

(figuratively) to go back to school (especially as an adult)

(figuratively) to keep a cool head, to remain level-headed

(figuratively) to be in a quandary, to be unsure of what to do, not to know where you stand

(figuratively) to be skin and bones (to be emaciated; to be very skinny)

(simile, informal) very rapidly, as fast as greased lightning

(informal) to badmouth, to slag off, to backbite, to speak ill of, to talk about someone behind their back

to be dressed to the nines, to be dressed to kill