题干
The World Health Organization has given some advice on how to protect us from infected(感染) with H7N9.
A：be
B：being
C：to be
D：are
答案(点此获取答案解析）
B
The World Health Organization has given some advice on how to protect us from infected(感染) with H7N9.
A：be
B：being
C：to be
D：are
