The scientific research on how to protect the rare animals is ________. Many scientists are working hard to find new way to raise the animals by man.
Many students believe that the choice of their universities and courses should __________ their own interest.
− Do you know the most ancient city in China ─ Xi’an well? − No, this is the first time I ___________ here.
My son has changed so much that I could hardly __________ his voice on the phone.
He must be leaving our village because he is __________.
− Can you _________ all the money that I should pay? − Very sorry. Please wait a minute, madam.