Advenir

advenir = to happen. It conjugates like "venir" (to come), but is only used in 3rd person, and most of the time singular, as in:

• quoi qu'il advienne,... = whatever happens,...
• advienne que pourra = do what there is to do

Now, let's take a look back at venir:

• je viens ('s' is silent)
• tu viens ('s' is silent)
• il vient ('t' is silent)
• nous venons ('s' is silent)
• vous venez ('z' is silent)
• ils viennent (pronounced "vienne")

There are many more verbs that consist of a prefix + venir, such as:

• circonvenir = to circumvent
• contrevenir = to contravene
• convenir = to agree
• devenir = to become
• intervenir = to intervene
• parvenir = to reach
• revenir = to return
• (se) souvenir = to remember
• subvenir = to support (someone's needs)
• survenir = to occur, to happen

and they all conjugate the same way.