Sometimes large blocks of ice are left behind and isolated from the retreating mass of the main glacier, and later melt to form kettle lakes in depressions in the moraine.
(large blocks of ice; are left; behind; T:Sometimes) (large blocks of ice; isolated; from the retreating mass of the main glacier; T:Sometimes)
large blocks of ice large blocks of ice
are left isolated
behind T:Sometimes
from the retreating mass of the main glacier T:Sometimes