是宾语从句 但是当宾语从句里陈述的是客观事实的时候 动词不必和前面的时态一致 所以加拿大是个好地方 这句话是个客观事实 并不随着说话的时间不同而改变 所以is不用过去式经典的例子就是teacher said that the moon...teacher said that the moon goes around the earth,这句话that可不可以省掉？？？拿请帮我把I heard Canada is a good place for sightseeing这句话改成（a good place to do）的形式，谢谢O(∩_∩)O，我会最加分的！！~~可以省掉 I heard Canada is a good place to sightsee