一道关于倒装的有疑问的题目：Only after my friend came＿＿.A.did the came repair B.he repaired the computer C.was the computer repaired D.the computer was repaired 我选A.【疑问】老师有讲过实义动词的倒装要借助助动词来实现.这道题的repaired是个实义动词,又是过去时,应该用did来实现倒装啊.为什么用was?