她解释说因为要加班，所以不能来参加聚会。
She explained that she couldn't come to the party because she had to work.
▼点击显示答案
couldn't英 /ˈkʊdnt/|美 /ˈkʊdnt/
解释
couldn't 是情态动词 can't 的过去式形式，在间接引语中表示过去所陈述的「不能」。原直接引语中用的是 can't come，转述时变为 couldn't come，属于时态后移。
She explained that she couldn't come to the party because she had to work.
couldn't 是情态动词 can't 的过去式形式，在间接引语中表示过去所陈述的「不能」。原直接引语中用的是 can't come，转述时变为 couldn't come，属于时态后移。