To suggest that something happened in the past... perhaps it is just me, but does this question seem a little unnecessary?
The past tense is used to talk about something that has happened in the past. It is used with verbs. For example, I learned how to use the past tense last week.
The past tense is trialed (US English) or trialled (British English)
The past tense is realised (British English) or realized (US English)
The past tense of label is labeled (in American English) or labelled (in British English).
Born is past tense.
The past tense of "she speaks English" is "she spoke English."
You use the past tense form which is 'had'.
The past tense of study is studied. I want to study English when I go to college. I studied English when I was in college.
The past tense of "learn" is "learned" in American English and "learnt" in British English.
The past tense of "label" is "labeled" in American English and "labelled" in British English.
Is can be used in the past tense if it's in its past tense form, which is was.
The verb is also spit. Spit is only used as the past tense is US English. In British English, the past tense is spat.