Explain in a few words “that inward eye / Which is the bliss of

Reading Comprehension: Read the quoted parts carefully and answer the questions in English. Write your answers in the corresponding space.For oft, when on my couch I lie In vacant or in pensive mood, They flash upon that inward eye Which is the bliss of solitude; And then my heart with pleasure fills, And dances with the daffodils. 
Explain in a few words “that inward eye / Which is the bliss of solitude”.
【正确答案】：

IT REFERS TO ONE’S MIND. 

【题目解析】：引文中的“that inward eye”指的是人的思想。