为什么是Who bought a new car?而不是Who did buy a new car?

为什么是Who bought a new car?而不是Who did buy a new car? he bought a new car .改疑问句did he bought a new car?还是 did he b 填空 1.Mr Lee bought a new car two weeks ago.(buy) 2.The car l I ___you have bought a new car. He bought a new car是什么时态 He decides ________(buy)a new car ___I can buy a new car填空 a big new car 还是 a new big car 为什么 1.Tom has bought a new car.Sue has bought a new car too.(改为同 who bought a new bike yesterday?疑问句中动词不是用原型嘛?为什么这里用bought而不是 1、 “Why didn't you buy a new car?” “I would have bought one I decided I would buy a new car= I( ) ( ) buy a new car