The past tense form of sweat is still sweat. Present ex: "I am sweating." Future ex: "I think I will sweat in gym tomorrow." Past ex: "I sweat so much yesterday."
I sweated today is correct. Sweat is a regular verb which means the past tense ends in -ed. It is becoming more acceptable in some dialects to use "sweat" as the past tense but this is non-standard.
the past tense of am is was and the past tense of has is had
The past tense of "has" is "had" and the past tense of "have" is "had."
Was and were are both the past tense of be. The present tense is: I am he is you are they are The past tense is: I was he was you were they were
"will be" is the future tense of "be". The past tense of "be" is "was/were".
The past tense of "she do" is "she did."
The word "were" is past tense. It is the past tense of the verb "to be."
The past tense of "will" is "would" and the past tense of "be" is "was" or "were" depending on the subject (singular or plural).
HAD is the Past Tense of TO HAVE.
The past tense of "am" is "was" and the past perfect tense of "has" is "had."
The past tense of "have" is "had."