Fisrt of all, comparing 持っています and もちます would be better, or 持っている and 持つ. 持っています means "something belongs to someone", "someone owns something" or "someone keep having / holding something for the duration (of time). 持つ is for the action 私はたくさんの本を持っています。= I have a lot of books. (These books are mine / belong to me.) 私は一日中、この辞書[じしょ]を持っていました。= I kept having/carrying this dictionary durling the day / all day long. カギと携帯電話[けいたいでんわ]を持って出かけました。= I left home with my key and cellphone. *There are more mening in 持つ but I wrote the basic one focusing on the difference you asked. I hipe this was helpful.