trip up on

She **tripped up on** the hardest part of the puzzle.

Phrasal-verb Difficulty

Meaning

to make a mistake when dealing with something difficult

She tripped up on the hardest part of the puzzle.

towards a higher position or level

a journey or excursion, especially for pleasure

to change plans or behavior to deal with obstacles effectively

to direct your effort toward a specific goal

to use knowledge or skills in a real situation

to move freight out for delivery

to gradually develop the ability to keep going for a long time

to make arrangements considering a specific factor or event