The water is very clear.
The water is from a lake.
Clear water could be from the tap or from a water bottle or from many other sources besides from a lake.
exists s1 x1.(n_water(x1) & r_very(s1) & Theme(s1,x1) & a_clear(s1))
exists p1 x1.(n_water(x1) & exists x2.(from(x1,x2) & n_lake(x2)))