How to play that hard measure:
Stand on your head, no I'm kidding...
1. Play those notes at various speeds, starting slow like a snail, then play at an ant's pace, then a human's pace, then a rabbit's pace....
REPEAT2. Play those notes while standing on one foot. This might work for some instruments and some students.
3. Play the first 3 notes of that hard measure with your left eye closed, again with your right eye closed, again with both eyes closed, again with your eyes open and one more time with your eyes closed.... Congratulations, that hard measure is memorized!
REPEAT4. Say each note name while taking a step. Maybe up the stairs would be fun. Add rhythm and say the note names.
5. Be partners. Partners alternate notes. Maybe then, partners each play 2 notes at a time.
REPEAT6. Write the notes several times on a piece of paper, either the note names or notes jotted on the staff.
7. Listen to the measure being played, then try and play it without the sheet music.
8. Make a board game or use a board from a game you already have... label each spot on the board with measure numbers. If the student lands on a spot that says "5", then the student should play the 5th measure. Eventually they will land on the hard measure and have to play that one that gives them trouble.
Whether your student is an audio, visual or kinesthetic learner, you can customize a way for them to learn those hard measures.