—I have difficulty __________ the article.—Remember __________ it three times at least.
We know that about seventy percent _____ the earth _____ covered by water.
you drive, you will be.
The policeman asked the child ________ cross the street ________ the traffic lights turned green.
— I have great _______in finishing the work by myself. Could you help me?— No problem.
-How well she sings!-Yes, she has a very sweet __________.