1. 早晨;上午(从人们通常醒来到中午或午餐前的一段时间)
The morning is the part of each day between the time that people usually wake up and 12 o'clock noon or lunchtime.
e.g. During the morning your guide will take you around the city...
导游上午会带你们游览全城。
e.g. On Sunday morning Bill was woken by the telephone...
星期天早晨，比尔被电话铃声吵醒了。
2. 凌晨，早晨，上午(从子夜到中午的这段时间)
If you refer to a particular time in the morning, you mean a time between 12 o'clock midnight and 12 o'clock noon.
e.g. I often stayed up until two or three in the morning...
我经常凌晨两三点才睡。
e.g. The attack happened in the early hours of the morning.
在凌晨发起了进攻。
3. 第二天上午;次日上午
If you say that something will happen in the morning, you mean that it will happen during the morning of the following day.
e.g. I'll fly it to London in the morning...
我明天上午会把它用航空快件寄到伦敦。
e.g. Melanie promised that she would call them in the morning.
梅拉妮许诺第二天上午给他们打电话。
4. 日日夜夜;夜以继日；一直
If you say that something happens morning, noon and night, you mean that it happens all the time.
e.g. You get fit by playing the game, day in, day out, morning, noon and night.
从早到晚都坚持做这项运动，日复一日，你就能强壮起来。