Learn Farsi: او باید ماهی‌تابه را در سینک گذاشته باشد. - He must have put the frying pan in the sink.

To express a logical deduction about the past (meaning you are pretty sure it happened), Farsi uses باید (must) followed by the Present Perfect Subjunctive. You form this tense with the past participle of the main verb—here, گذاشته from گذاشتن (to put)—plus the subjunctive form of "to be", which is باشد for the "he/she" form.

Does ماهی‌تابه literally mean "fish pan"?

Yes! It is a compound of ماهی (fish) and تابه (skillet or pan). Even though it translates literally to "fish pan", it is the standard everyday Farsi word for any frying pan, regardless of what you are actually cooking in it.

Why do we need the word را after ماهی‌تابه?

The word را is used to mark a specific, definite direct object. Because the sentence refers to "the" frying pan—a specific pan that the speaker and listener know about—we must use را. If we were talking about him putting just "a" frying pan in the sink, we would use یک ماهی‌تابه and drop the را.

Is سینک just the English word for "sink"?

Exactly. سینک is a direct loanword from English and is the most common way to refer to a kitchen sink in modern spoken Farsi. Another word you might occasionally hear is ظرف‌شویی (literally "dish-washing place"), but سینک is perfectly natural and widely understood.