You can get Laban key for Android and it's 1 tap to go from Vietnamese to English. I feel like the complaints about the sometimes quirky translations is ridiculous. This is a free app. There's a lot of programming here. Do you want to pay a programmer to guess every possible correct translation ? That's a lot of time. Think of the word soda or is it soft drink? What about pop or carbonated beverage etc.... Don't take it personal when you get a few wrong. Give it what it wants and move on. I've been to Vietnam and feel this app captures the subtle differences in expression. Thanks Duolingo!!
I do really appreciate the Duo program, but I do both Spanish and Vietnamese in it (and I see you do too!) and I notice a lot of difference between the two languages. The Spanish accepts TONS of translations, and also the English is correct 99% of the time, whereas with the Vietnamese version the English is quite frequently wrong. There should be a VN-English-VN translation process to work on corrections, or English-VN-English, depending on if we're translating to or from. That would eliminate most of the problems.
"You want to exist or want to live" is a statement in English, not a question. Add "do" to the beginning of the sentence and it becomes a question. As it often does, Duo has provided an incorrect English sentence and requires that you spit back the incorrect English to complete the exercise. I have seen Duo respond to comments occasionally and make some changes based on comments, but for the most part commenting is a waste of time. Nobody is home at Duo.
The word bubble approach does not have a "do" in it so you can't construct a realistic/correct English sentence (which apparently it accepts but I can't verify this) with "Do" in it. The bubbles let you say "You want to exist or (to) live" which is a statement, not a question. To make the correct "Do you want to exist or (to) live" you have to type it in manually, which is not terrible, but the text bubbles should give you all the words you need to make the correct sentence