Mr Shaw showed us around his small museun last Friday.(改为被动语态）

填上were showed就可以了呀，被动语态的过去式嘛！！

We were showed (by Mr Shaw) around his small museum last Friday.

do did done

show showed shown （其实考点就是考 show 的过去分词）

被动态基本形式为 be + done

而是该同义句时态为过去时，所以答案是 were shown

were showed