【2013山东菏泽】The World Health Organization has given some advice on ______to protect us from being infected(感染) with H7N9.
A.how | B.what | C.where | D.when |
【2013山东菏泽】The World Health Organization has given some advice on ______to protect us from being infected(感染) with H7N9.
A.how | B.what | C.where | D.when |