Sunken is not a verb so it doesn't have present or past tense.
Sunken is an adjective
No, "sunken" is a valid past participle form of the verb "sink." It is commonly used in phrases like "the ship has sunken to the ocean floor" to indicate that something has descended to a lower level or position.
past: I was; you were; he/she/it was present: I am; you are; he/she/it is
Have is present tense. The past tense is had.
There is a past, present, and future. There was a past; there is a present and there will be a future.
what is present past
Present - am. Past - was and were.
Past - was Present - is Future - will be
past: I did, you did, he/she/it did; present: I do, you do, he/she/it/does
Present tense - clean. Past tense - cleaned. Present tense - work. Past tense - worked. Present tense - play. Past tense - played.
Seek is present tense, and seeking is the present participle. Sought is the past tense and past participle.
Past - was and were. Present - am, is and are.
Studied is the past participle of study. Studying is the present participle.