The pronoun us is the plural first person objective case. It has no past tense: only verbs do.
The past tense of "mean" is "meant."
The past tense of "mean" is "meant," and the past participle is also "meant."
The simple past tense of 'am' is 'was' or 'were'
The past tense form of "mean" is "meant."
Kneed is the past tense of knee. If you mean knead, the past tense is kneaded.
If you mean writhe, the past tense is writhed.
The past tense is "I meant." (pronounced ment)
The past tense of "slide" is "slid."
The past tense of "teach" is "taught."
The past tense is realised (British English) or realized (US English)
The past tense is trialed (US English) or trialled (British English)
I think you mean "decide", which is "decided" in the past tense.