Some experts advise that steps ________ to protect the river at once, otherwise it's dangerous for people to drink the water.
A.being taken
B.be taken
C.were taken
D.had been taken
网友回答
B解析advise表建议，劝告，后接宾语从句时从句谓语动词应用should+动词原形形式，表示的是虚拟语气，其中should还可省略。steps和take之间是被动关系，因此正确