He opened the envelop, had it_____ and began to read it
A.unfoldingB.foldingC.unfoldedD.folded在线课程C
考查非谓语动词。Unfold展开；fold折叠；合拢。句意：他打开了信封，把信展开开始阅读。使役动词加动词的过去分词表示把某事做了。结合语境可知是展开信，故选C。原答案有误。