the professor is said___another important discovery为什么是to have ma_英语解答

the professor is said___another important discovery为什么是to have made而不是having made

人气：204 ℃　时间：2020-03-29 08:37:22

解答

to在此表目的 havingdone 表示过去进行时,而此句谓语动词是is是一般现在时的目的...