Take another look at the sentence:
While Karen was cleaning green peppers at the sink, Chris __________ a long, fat anchovy onto the pizza, camouflaging it with sliced mushrooms and onions.
Chris put the anchovy on the pizza. Thus, you need a form of lay. 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|