Learn French: Ils auront découvert un métal et une ressource. - They will have discovered a metal and a resource.

We use the future tense of the helping verb avoir (which gives us ils auront for 'they will have') and add the past participle of the main verb, découvert (discovered).

Why does the past participle découvert end in a 't' instead of the usual '-i' for an '-ir' verb?

The verb découvrir (to discover) is irregular. Verbs ending in -couvrir and -vrir (like ouvrir, to open) have past participles that end in -vert. Therefore, découvrir becomes découvert.

Since there are multiple things being discovered, shouldn't découvert be plural?

No. Because this sentence uses avoir as the helping verb, the past participle (découvert) only changes to agree with a direct object if that object comes before the verb. Since the objects here (un métal et une ressource) come after the verb, the past participle stays in its default masculine singular form.

Is there a pronunciation link (liaison) at the beginning of the sentence?

Yes, there is a mandatory liaison between the subject pronoun Ils and the vowel-starting verb auront. You must pronounce it with a 'z' sound connecting the two words.