We must take measures to protect the environment from ．
A. polluting
B. being polluted
C. polluted
D. pollute
网友回答
A. polluting
(答案→)B. being polluted
C. polluted
D. pollute
解析：考查固定句型。Protect sb from sth/doing sth保护某人不受…伤害；根据本句意，又使用被动形式。句意：我们必须采取行动保护我们的环境不受污染。