Bob is ________crazy about Beethoven that he knows all his works well.

The lively boy suddenly appeared to be ________ quiet, so his mother knew something unusual must have happened.

—You don’t see the professor from Singapore quite often, do you? —No, we only meet ______．

He seems to be doing nothing, but _____ he is just waiting for his chance.

Camels were ____ better than horses for travelling a long distance.