Sawadogo experimented with digging wider and deeper pits and using stones. Sawadogo experimented with digging wider and deeper pits and using stones. But he stayed. But he stayed. His use of so-called zai pits has in four decades created a 40-hectare oasis of thorny acacia, yellow-fruiting saba and other trees near his village in Yatenga province, bordering Mali.
The sun is a very changeable energy.
( z0 energy :ARG1-of ( z1 change :degree ( z2 very ) ) :domain ( z3 sun ) :rel ( z4 possible :ARG1 z1 ) )
(z0 / energy
    :ARG1-of (z1 / change-01
                 :degree (z2 / very))
    :domain (z3 / sun)
    :rel (z4 / possible-01
             :ARG1 z1))
The sun is a very changeable energy .
z4 :ARG1 z1
z1 :degree z2
z0 :ARG1-of z1
z0 :domain z3
z0 :rel z4