说明不是强调句呗
强调句的that不能省的,而且去掉it is that必然是完整句子
这只是简单的动词不定式形式,类似于it is my turn to do ,it is my work to do是不是It is in Iran's interest that not to develop nuclear weapons 也是对的错的,你有见过 it is my work that to clean the room这种说法吗？你一定要弄成强调句，我建议这么写，不过只能很牵强It is Iran's interest that is not to develop....... 把in去掉，that后加is