We can't count on the good weather lasting.（我们不能指望这样好的天气会持久。）

He is at the end of his resources, too. Don't count on him for help.（他也束手无策，别指望他帮助啦。）

Few people can count on having a job for life.（几乎没有人能指望一辈子都干一个工作。）

You should fence in that field, roof in that courtyard and fill in that hole.（你应该在那块地上围上篱笆，在那个院子里盖上屋顶，并填上那个洞。）

In that war, many soldiers died in that fen area.（在那场战争中，许多士兵死在那片沼泽地带。）

nevertheless, there was something in that sky, in that hill, in that plain, in that tree, which was so profoundly desolate, that after a moment of immobility and revery he turned back abruptly.（然而，在那片天空、那座山、那片平原、那棵树中，有一种如此深邃的荒凉，他瞬间静止和沉思后突然转身回去。）

Beauty is lost or picked up in that instant, in that flick of the finger.（在那一瞬间，在那一弹指之间，美就失去了或者被拾起来了。）

Ann lives in that apartment.（安住在那套公寓里。）

I'm not counting on him to help us with the project.（我不指望他会帮助我们完成这个项目。）

Please count me in for the barbecue this weekend.（这周末烧烤请把我算进去。）

希望这些例句能帮助你理解"count on"的用法。