Of all the living creatures on earth,   34   of insects is the largest. Some insects are veryuseful to humans,   35   bees. People get honey and wax from bees. Some insects areextremely harmful, and they   36   a lot of damage, especially to crops. Locusts are perhapsthe most dangerous of all   37   they will eat every green plant. When millions of them showup on cultivated land, they soon leave it bare. In some countries, they are the farmer’s greatestenemy. Another nuisance is the common fly,   38   it worries us indoors and outdoors, butalso because it spreads disease.
【題組】34.
(A) the number
(B) a number
(C) an amount
(D) the amount