A Microsoft Word error...??

Question

I was typing a Spanish sentence into Microsoft Word (the language dictionary was set to Spanish), and a red wiggly line came under the word, 'mostra' from mostrar= to show. What's the problem, what grammatical error have I made? I'm trying to say, 'these young people are rude and their lack of respect for the teacher shows how they are going...' As far as I know (correct me if I'm wrong), I need to put 'it shows', so I would use 'mostra'.

This is the sentence: 'Estos jóvenes son grosero y su falta de respeto para el profesor, mostra cómo van....'

Answer 1

Estos jóvenes son groseros y su falta de respeto hacia el profesor muestra cómo van...

Answer 2

I was about to say that it's not an error with Word. "mostra" simply does not exist, it should be muestra, since mostrar is a stem-changing verb.