现在完成时have/has + 过去分词。
用have还是has,要根据主语的人称来确定。
第一人称(I)
I have turned off the light.
第二人称(you单数)
You have turned off the light.
第二人称(you复数)
You have turned off the light.
第三人称(he/she/it)
He/ She/ It has turned off the light.
总结:第一人称,第二人称作主语时,用have。第三人称作主语时用has。
明白了吗。