Chinese languages

hi, i was wondering how would u say "why" in different context as in
what sort of "why" would i use for

"why was the bus late?"

and

"why won't you come home early"

if these two use the same type of "why" then please state another example cos i can't think of any..

plus if you know cantonese, (i speak cantonese) please tell me the equivalent of these cantonese 'whys' in mandarin thank u.

din guy= ?

dim yurng= ?

i'm sure you know what i mean there.

Why is 为什 (wei4 shen2me) and/or 怎?zen3me, which is also "How"); they're interchangeable (there's no special context for each as far as I know).

Cantonese's "Dim Gaai" translates to the above in Mandarin, while "Dim Joeng" is 怎?amp;#26679; (zen3me yang4).

If you want to speak real Mandarin in real life, it is better to say che1 zen3me lai2 wan3le (why was the bus late). It is rarely to use wei4shen2me because it is too formal to be used in daily life. If you are angry why the bus was late, you can use wei4shen2me and stress it or use
zen3me and stress it. So you don't want to remember hundreds of words, it is ok to only remember "why" is zen3me in daily life.