因为这里是不及物动词,agree一般与with连用,agree with sb.,表示同意某人的观点
agree vt.＆ vi.基本用法如下
1)单独使用,表示同意、答应等.如：
①I asked him to help me and he agreed.
我请求他帮忙,他答应了.
②After a short time,the program was agreed.
过了一会儿,这项计划大家都同意了.
2)跟介词with连用.表示"同意；赞成"；"与……一致；(气候,食物)适合".
例如：①I quite agree with what you said.
我很同意你说的话.
②I don"t quite agree with their methods(opinions,ideas).
我不太赞成他们的办法(意见,想法).
③The verb must agree with the subject in person and number.
动词在人称和数上应与主语一致.
④The enemy generals could not agree with one another; they quarrelled the whole night.敌军将领意见不一致,争吵了一整夜.