"Please have some fish" 的英文说法是 "Please eat some fish."
"Please" 是礼貌用语，意思是 "请"，"have" 是动词，意思是 "吃"， "some" 是冠词，意思是 "一些"， "fish" 是名词，意思是 "鱼"。
例句：
"Please have some fish for dinner tonight." (请今晚晚餐吃些鱼)
"I made too much fish, please have some." (我做了太多鱼，请吃点)
"Please have some fish, it's very healthy." (请吃些鱼，它非常健康)