Tom _______(can’t/mustn't) be at home .he said he would go to Lily‘s party in the afternoon.

问题描述:

Tom _______(can’t/mustn't) be at home .he said he would go to Lily‘s party in the afternoon.
如题,请讲一下理由.

can't
can't表示否定猜测“不可能”
既然说了会去另一个人的聚会,就没可能在家