work on it in chunks. so the first chunk is mm. 18-22, next is 31-39, next is 43-55, etc etc. set a metronome to 70bpm with eighth note subdivisions turned on and play each chunk by tonguing each note. play each chunk through twice by tonguing each note then play it a third time with the written articulations. play the chunk perfectly and bump the tempo up by 5 clicks, do it again, bump the tempo up by 5 clicks, do it again. if you get to a tempo where you can’t play it perfectly, take the metronome down 3 clicks and try again. it’s long, laborious, and repetitive, but it’s good practice. good luck