what the different ?

[foong]

1) tau tu and xe lua, are they the same ? why they are different ?

2) tang and bieu , are they the same ?

[bhtbht]

1) I don't understand what "tau tu" means. Do you mean "tàu hỏa"? If so, I believe that "tàu hỏa" and "xe lửa" have different origins. However, I don't exactly know how they're different. They seem to be the same in their meanings.
2) The two words are the same of definition. But they are slightly differrent in emotional tone. "Tang" is more formal than "bieu", to me. Most of cases, I think they are quite equivalent.

[foong]

1) tau hoa and xe lua = are the same

2) Tang and bieu = are the same, where else tang is more formal

Thank you, bhtbht

[bhtbht]

You're welcome.