1. 'Then' at the end of a sentence serves the same function as 'So' at the beginning or middle. 'I'm hungry.' 'So have something to eat.' 'I'm hungry.' 'Have something to eat, then.' 2. 'Though' at the end of a sentence serves the same function as 'But' at the beginning or middle. I did the test, but I found it difficult. I did the test. I found it difficult, though. Both of these forms are very common is natural speech. If you listen to native speakers, you'll hear these words used a lot at the ends of sentences. And if you analyse what they're saying, you'll see that 'then' and 'though' just mean 'so' and 'but'.

"Though" has the same meaning as "however." It shows a contrast. I wanted to go outside. However, it was too cold. I wanted to go outside. It was too cold, though. "Then" mean something similar to "in that case." It's cold out. I'll put a jacket on, then. It's cold out. In that case, I'll put a jacket on. (Then can also be used as a time word. "I'll see you then!")

"My family have (has?) dinner at 6:00pm. But I'm on the train then." Seems like "then" could be replaced by "meanwhile".

Could you give an example of a sentence?