ACT Conventions of Standard English Practice Test 2026 – Your Complete Guide to Mastering the Exam!

Lie (to recline) has its own set of forms: lie, lay, lain, lying. The past tense is lay, but the past participle used with has/have/had is lain. That’s why the correct form here is lain. The other options come from the verb lay (to put down): lay is the past tense of lie, laid is the past participle of lay, and laying is the present participle of lay. So the past participle of lie (down) is lain, which fits the sentence when forming perfect tenses like has lain or had lain.