David,howoldisyourfatherthisyear—______.Andwejusthadaspecialpartyforhis_____birthdaylastweekend.

cycling is a fantastic way to burn a few calories and save some money, there still exist risks

Tom is so worried about the test that he said he was going to study all night.—-Tell him he should quit _________and get some help.

These animals are all used to their environment,______, they have learned how to live successfully in their habitat．

“It’s too cold. Would you mind _________ thewindow”. – “_________ . But don’t do it now.”