Take another look at the sentence:
The last slice of cheesecake __________ on a platter in the middle of the table; everyone wanted to eat it, but only Cassandra was assertive enough to scoop the slice onto her own plate.
The slice of cheesecake rested on the platter. Thus, you need a form of lie. Since the sentence is past tense, you need the simple past form. Consult the table below or review the rules.
|Infinitive||Definition||Simple Present||Simple Past||Past Participle||Present Participle|
|to lay||to put something down||lay(s)||laid||laid||laying|
|to lie||to rest or recline||lie(s)||lay||lain||lying|