the next word starts with a vowel and consonant, or only before adjectives starting in u and eu when they sound like you.

the next word starts with a consonant, or before words starting in u and eu when they sound like you.

the next word starts with a consonant (a,e,i,o,u) or with a mute h.

the next word starts with a consonant (c,d,l,m,z) or with a mute h.