On account of fuel supplies being finite and many people being wasteful, we will have to install ________ solar heating device in our home.
So difficult____it to work out the problem that I decided to ask Tom for advice.
_______homework did we have to do that we had no time to take a rest.
Only then___________ how much damage had been caused.
In the dark forests ________, some large enough to hold several English towns.
Little _____ about his own health though he was very ill.