The World Health Organization has given some advice on________to protect us from being infected(感染)with H7N9.
It was dark I couldn’t see anything.
Many people didn’t realize the importance of health _______they have fallen ill.
— Would you like to climb the hill with us tomorrow? — If it ___________ ,I ___________.
–Do you know ______? –To meet her friends from America.
— Could you tell me ___________? —No problem.