There was less food for birds and also for the Prairie dog, an holes in the ground.
Although he knew little about the large amount of work done in the field, he succeeded ________ other more well - informed experimenters failed.
—Is the experiment easy? — ________ . I’ll just do my bit.
Apples are usually sold by ________ weight and eggs are sometimes sold by ________ dozen.
.---Will someone go and get Mr. Black? ---He’s already been ___.
__ with such great difficulty, Jack felt at a loss ___.