问go to sleep的过去式

go to sleep是去睡觉的意思，过去式可以从以下例子看出：

Last night I was very tired, that is why I went to sleep around 7 o'clock in the evening, now I feel much better, full of energy. 昨晚实在是太累了，所以晚上七点就睡了，现在感觉好多了，精力充沛。