Call it a day: (=Basta por hoy) stop working; to decide to quit working and go home.David called it a day and snuck out of the office a little after 3:00.
Call someone's bluff (=poner en evidencia).
Explanation: Usually used to state that you do not believe what someone is saying or that you think they are exaggerating. Also used in poker.
Examples: I called his bluff and he admitted he had made up the whole story. - I called his bluff - he only had an Ace and a pair of twos.
Can't make heads or tails of something: (=No encontrar ni pies ni cabeza, no tener sentido") John is so strange. I can't make heads or tails of him. Do this report again. I can't make heads or tails out of it.
Can't see the forest for the trees (= Los arboles no dejan ver el bosque): you can't see the entire forest because the trees are in the way. Something small prevents the view or understanding of something large.
Maritza gets too distracted by small problems at work. If she can't see the forest for the trees, she'll never get ahead in the company.