D,还原成陈述句看,this is the museum (that) which they visited last month
有一个类似的,this museum is what they visited last month(非定语从句,好像是主语从句)
D,还原成陈述句看,this is the museum (that) which they visited last month
有一个类似的,this museum is what they visited last month(非定语从句,好像是主语从句)