what is the difference between gerund and infinitive also give reason?

Some verbs have different meaning. (when used with Gerund or Infinitive)

GERUNDINFINITIVEforgetHe'll neverforget spendingso much money on his first computer.Don'tforget to spendmoney on the tickets.

GERUNDINFINITIVEgo onGo on readingthe text.Go on to readthe text.

GERUNDINFINITIVEmeanYou have forgotten your homework again. Thatmeans phoningyour mother.Imeant to phoneyour mother, but my mobile didn't work.

GERUNDINFINITIVErememberIremember switching offthe lights when I went on holiday.Remember to switch offthe lights when you go on holiday.

GERUNDINFINITIVEstopStop readingthe text.Stop to readthe text.

GERUNDINFINITIVEtryWhy don't youtry runningafter the dog?Itried to runafter the dog, but I was too slow.