我国台风、寒潮、旱涝灾害频繁,对管道运输十分不利。
He thought his marketing plan was perfect, but ____(正相反), it was not and it failed.
《孟子》是一部记录 的思想观点和政治活动的书,共七 篇。南宋朱熹将《孟子》、____ 、____ 、____ 并称为“四书”。