a half hour later\after half an hour\after half an hour later\half an hour later分别是什么意思?

a half hour later\after half an hour\after half an hour later\half an hour later分别是什么意思?
a half hour later\after half an hour\after half an hour later\half an hour later分别是什么意思?

a half hour later\after half an hour\after half an hour later\half an hour later分别是什么意思?
我语法不是很好.
单单就字面上的意思给你做下阐述.
都是半小时之后的意思.就是根据不同时态而选择.