Complete the detective's frustrated case notes by choosing the correct word for each blank.

We could have caught the phantom thief if we had noticed those muddy footprints earlier.

We could have caught the phantom thief if we had noticed those muddy footprints earlier.

The third conditional can use modal verbs like could or might instead of would to show possibility in the hypothetical past.

The main clause uses could have + past participle (caught).

The "if" clause uses the past perfect (had noticed) because it refers to a missed opportunity in the past.