I have already bought a sweater for my mother as a birthday present．(改为否定句)I________bought a sweater for my mother as a birthday present________．A.haven't．alreadyB.don't have，yetC.have not，yetD.do not have，yet
网友回答
C解析分析：本句中的谓语动词是have bought，have是个助动词，否定结构必须是have not bought(haven't bought)，另外already是用在肯定句里的，改为否定句时要改为yet．