Lilo & Stitch C1 Grammar Quest

Choose the sentence that correctly uses a perfect modal for speculation about the past:

• Lilo must warn Stitch about the galactic bounty hunter.
• Lilo should have warned Stitch about the galactic bounty hunter.
• Lilo might warn Stitch about the galactic bounty hunter.
• Lilo must warning Stitch about the galactic bounty hunter.

Explanation

Should have + past participle indicates a past action that would have been wise or necessary but was not performed.