According to my dictionary, the English phrase 'it is getting dark' in Latin is
advesperāscit (from advesperāscere, -vit)
I have not started learning 3rd conjugation verbs yet, but this looks like one. The questions I had were:
1) The entry in the dictionary was not listed in the 4-prinipal parts format I've seen so far. I know some verbs do not have all four prinicpal parts so that's ok, but now I am not sure ...