The sky appears clear.
There are no clouds in the sky.
no clouds would definitely make the sky clear
exists e1 p1 x1.(n_sky(x1) & exists s1.(Theme(s1,x1) & a_clear(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_appear(e1))
exists p1 x1 x2.(n_sky(x2) & in(p1,x2) & -exists x3.((x1 = x3) & n_cloud(x3)))