YOU SAID:
What the firetruck is going on
INTO JAPANESE
消防車が何をしているのか
BACK INTO ENGLISH
What fire engines are doing
INTO JAPANESE
消防車がやっていること
BACK INTO ENGLISH
What a fire engine is doing
INTO JAPANESE
消防車がしていること
BACK INTO ENGLISH
What a fire engine is doing
That didn't even make that much sense in English.