The correct answers are We require an honest goblin for the bank., Please buy a unicorn horn for the spell., and I need an umbrella for my pet toad.

The rule for "a" vs. "an" depends on the sound at the beginning of the next word, not just the spelling!

• "Honest" starts with a silent 'h' (a vowel sound), so it takes an.

• "Unicorn" starts with a 'y' sound (a consonant sound), so it takes a.

• "Umbrella" starts with a vowel sound, so it takes an.

• "Wooden" starts with a consonant sound, so it should be a wooden wand.

• "Eye" starts with a vowel sound, so it should be an eye.