"The class started at nine thirty" was accepted (11/14/18). "Nine thirty" should be the primary answer, because "half past nine" is not a common expression in the US.
They educated urban parts and most educated rural parts that r not filled with foreigners who make up their own English
Wouldn't we usually say "the class", not "class", in English? Or in the USA, is just "class" usual? I don't think it is in the uk
It can be used either way in the US. Having it this way makes me think of a teacher saying it to a student who came in late. In that case, which class isn't in question, so we'd often drop the article on this side of the pond.
This question is a mess. The only thing that's accepted is the exact statement: Class started at half past nine I had the following marked incorrect: Class started half past nine, Class started at nine thirty, Class started nine thirty, Class started 9:30, Class started at 9:30
It's funny how "nine thirty" is wrong, when I by accident wrote 12:30 and it was marked correct.
In the United States if one would say half past nine, (although common until the mid-twentieth century), listeners would assume that you had been reared on an isolated mountain with little interaction with civilized individuals. Now that may be a bit of a stretch, but in today's digital world the time would be presented as 9:30. Dúo is still not accepting it.