Question

As everyone knows, rubbish           everywhere.
A. need be thrown      
B. mustn’t be thrown      
C. can’t throw            

Answer 1

B

考察情态动词用法。Mustn’t禁止，千万不能；根据句意可知B正确。句意：正如大家所知，千万不能随处乱扔垃圾。