"In the twentieth century, I was happy."
Translation:Ve dvacátém století jsem byl šťastný.
this here is a rare case we have evidence of what the linguists call theme vs rheme in english. in plain terms, the english sentence is not about when the dude was happy but about how he was doing in the 20th century. the pre-position of the adverbial is significant. to make the czech sentence match the theme/rheme with your word order, one would have to use a weird sentence intonation.
Firstly, the auxiliary verb must be strictly second position. Secondly, adverbials in Czech are not separated by a comma as in English, they must be an integral of the sentence. Thirdly, as nueby shows, the topic and the comment (the rheme and the theme) are clearly distinguished here. The comment is expected to be sentence-final. See https://en.wikipedia.org/wiki/Topic_and_comment
Dobré ráno. I reported this as "something else went wrong." I didn't get the question wrong. Instead, I got one of those gentle 'typo' reminders. Duo said I should have typed V instead of Ve.
Obviously, from the page header, the main translation uses Ve. And then I have this from the Tips for the Numbers 2 skill Use ve before a two-consonant sequence ending in a consonant other than "l", "r", or "ř", which of course would supports the use of ve.
I'm interested in what is correct. Maybe usage supports both?