on sunday morning是什么时态

　　例句：

　　Dr. Keen arrived about seven on Sunday morning.

　　基恩博士是星期天早上7点左右抵达的。

　　On Sunday morning Bill was woken by the telephone

　　星期天早晨，比尔被电话铃声吵醒了。

　　He enjoyed a round of golf on a Sunday morning.

　　他喜欢星期天的上午打一场高尔夫球。

　　There're always a lot of people on Sunday morning.

　　星期天早上总是有很多人。