Although water is still the main agent of erosion in deserts, wind is a more important agent of erosion in arid regions than in humid regions.
(water; is; T:still; the main agent of erosion in deserts) (wind; is; a more important agent of erosion in arid regions than in humid regions)
water wind
is is
T:still the main agent of erosion in deserts
a more important agent of erosion in arid regions than in humid regions