"Ai phát minh tàu hoả?"
Translation:Who invents the train?
I know that in Vietnamese they use the present tense, but in English we would certainly use the past tense: "Who invented the train?"
This sentence should be "Ai phát minh RA tàu hỏa", the word "ra" is a required complement for the verb "phát minh" in this case.
Also, "who invented the train?"
I can't wait that long. Does somebody invent another kind of vehicle next week?
Sometimes James Watt invents it. But he doesn't invent as often any more now that he's dead.