For question 1-7,choose the best answer from the four choices marked A B C and D .

问题描述:

For question 1-7,choose the best answer from the four choices marked A B C and D .
在这个句子中为什么要用marked,而不用mark,有必要用过去式吗?

表示被动,不是过去式,原句是choices that are marked.是一个定语从句