--Let's make it ---half past eight-----the morning.填什么?答案给了“

--Let's make it ___half past eight_____the morning.填什么?答案给了“/；on”我怎么觉得是“at；on”
make it作 定时间 用不是接at吗?
题目错了应是--Let's make it ___half past eight_____the morning of June 21st