Examples:
1) Water boils at 100 degrees Celsius. (fact)
2) The sun rises in the east. (fact)
3) He usually carries her bag for her.
4) I normally go to school by bike, but today I am taking the bus.
5) We often stay at home these days because of Covid19.
RULE: stam ww. Bij he/she/it stam+s/es/ies.