The past tense of can is used which is could.
They could have given some cake to me.
The negative form, can't is used with present perfect:
They can't have eaten the whole cake!
Present perfect, past perfect or future perfect.
"Cannot" can't be used in the present perfect tense.
"Have" is present. "Had" is past tense
Present Perfect Tense: I have; You have; he, she, it has; we have, you have, they have Past Perfect Tense: I had; you had; he, she, it had; we had; you had; they had Future Perfect Tense: I shall have; you will have; he, she, it will have; we shall have; you will have; they will have Note: has is used in the third person, singular present perfect tense.
The present perfect tense is used when there is a connection with the past and the present. It is used to depict change, experience and a continuing situation. The future perfect tense, however, is used to talk about the past in the future.
Have can be present simple tense: I have a new car.Have is used in present perfect tense: I have bought a new car.Had is the past tense of have.Had can be used in past simple: I had breakfast early today.had is used in past perfect: I had seen the movie before.
Present tense
You have seen is the present perfect tense of you see.
present perfect = subject + have/has +past participle.I have eaten all the rice. She haseaten all the vegetables.past perfect = subject + had + past participle.I had walked to town. She had caughtthe bus to town.future perfect = subject + will + have + past participleI will have left town by then.All these sentences use the past participle ( in italics) the use of the other words (in bold) determines what tense the sentence is.
Have and has are both used in the present perfect tense:I/You/We/They have learned.He/She/It has learned.
The present perfect tense is used to express experience, change or a continuing situation.
The present perfect tense is Have/Has Hidden.