Question

Some problems ___ in the lecture by Mr.Smith are very popular in our school, such as the waste of electricity, water and food, etc...

A．referring

B．referred to

C．referring to

D．were referred

Answer 1

B

考察非谓语动词。句意：在讲座上被史密斯先生涉及到的一些问题带我们学校非常普遍……，过去分词作定语表示被动的，发生过的动作，problem是涉及的对象，故选B。