Subject + had + V.3 + Object.
ใช้บรรยายเหตุการณ์ในอดีตที่เกิดขึ้นก่อนอีกเหตุการณ์ในอดีต
Examples.
– He could not make a sandwich because he had forgotten to buy bread.
– When she enrolled on the course, she had never studied English language before.
– Buy the time I moved in, they had finished the building work.
– When I closed the door, I realized that I had left my key inside.
I Find Knowledge 