If anyone is wondering, почему is a compound word made out of по, which means ‘along’ or ‘according to’, and чему ‘to what’ (i.e. dative of что).
Thank you! затем is also a compound word. It is made out of за, in this case meaning ‘behind’ or maybe ‘at’, with the instrumental case of что (чем – meaning ‘with what’). отчего, on the other hand, is composed out of от, i.e. ‘from’, and чего, the genitive case of что (meaning ‘of what’).
If this sentence was phrased this way, you normally wouldn't put "the" in that sentence.
I'll just put a couple of notes here for any non-native English speakers reading this:
"Why are they not in the school?" / "Why aren't they in the school?" To me this suggests they might be, for example, outside the school playing. By contrast, "Why aren't they at school?" suggests they're not even anywhere near the school property.
"Why are they not in school?" To be "in school" in English means that one is enrolled as a student and actively attending. "She is in school" is like "she is employed" - it doesn't necessarily mean the student is at the school right now. There's a post further down on this page that explains the Russian equivalent.
keinemeinung wrote: You could say "Они ходят в школу?" (are they going to school?) or "Они учатся в школе?" (Are they studying in school?)
I can hear «в» (pronounced [f] because a voiceless consonant follows) pretty well.
On occasion--but not in this sentence, where I hear it just fine--I have caught the TTS omitting в completely on the slow speed when it is the first word in the sentence. If you come across that and agree it's problematic it might help for a native speaker to report it as well as us non-natives. :-)
Yes, «е» makes the previous consonant soft. So do ё, и, ю, я.
How would one say, "are they in school" referring to "in school" as in attending school for the year?
You could say "Они ходят в школу?" (are they going to school?) or "Они учатся в школе?" (Are they studying in school?)