The problem just ---in their diacussion is an important one.A,to be refered to B.referred toC.referring to D.referred 选b,why

The problem just ---in their diacussion is an important one.A,to be refered to B.referred toC.referring to D.referred 选b,why
The problem just ---in their diacussion is an important one.A,to be refered to B.referred to
C.referring to D.referred 选b,why

The problem just ---in their diacussion is an important one.A,to be refered to B.referred toC.referring to D.referred 选b,why
首先,the problem后面is前面的部分做定语,the problem is referred to,需要被动语态,排除CD,just刚才,需要过去时,排除A(A选项是将来),所以选B.完整的是The problem (which was) just referred to in their discussion is an important one.刚才他们讨论中提及的问题很重要.

选B的理由：
这个问题一定是被提到，表被动，所以只有B对。
因为问题是被别人提出来的。如果你选C就是问题自己提出表主动，这是不对的。
明白？
不懂你再问~希望帮到你