"slid" is already past tense. The present tense is "slide".
The past tense of "slide" is "slid."
slid is the past tense
The past tense of slide is slid
slid The car has slid off the road.
The past tense of "slide" is "slid."
slid
They slid.
Slid is already the past participle of slide. It's also the past tense.
slide slid Backslid
You may say "she slid across the ice" or "he had slidden all the way down the hill"
No, it is not. It is the past tense and past participle of the verb to slide. It can be a verb form or, very rarely, an adjective (e.g. slid bottle caps will pass under the door).
The present perfect tense of slide is "have/has slid." For example, "She has slid down the hill many times."