Below is an instruction that describes a task. Write a response that appropriately completes the request in Chinese. Please answer in Chinese.

### Instruction:
 丹尼斯收集了10块石头。他把它们都放进了鱼缸，但他的鱼吃掉了一半。他成功让鱼吐出两块。丹尼斯还剩下多少块石头？


### Response:
 鱼吃掉了一半，丹尼斯还剩下10/2=<<10/2=5>>5块石头。
他让鱼吐出两块，所以丹尼斯还剩下5+2=<<5+2=7>>7块石头。