a. The -a of the article may be elided before a word beginning with a vowel, or after a preposition ending in a vowel:
"L' espero, l' obstino kaj la pacienco."
"De l' montoj riveretoj fluas."
"Kaj kantas tra l' pura aero."
b. The final -o of a noun may be elided in poetry. The original accent of the noun remains unchanged:
"Ho, mia kor', ne batu maltrankvile."
"Sur la kampo la rozet'."
c. The final -e of an adverb is very rarely elided (except in the expression dank' al, which occurs in prose as well as in poetry):
"Ke povu mi foj' je eterno ekdormi!"
Dank' al vi, mi sukcesis, thanks to you, I succeeded.
THE PREFIX EKS-.
281. The prefix eks- is used to form words expressing a previous incumbent of a position, or removal from such position:
eksprezidanto, ex-president.
eksreĝo, ex-king.
eksigi, to put out of office, to discharge.
eksiĝi, to withdraw from one's office, to resign.
THE PREFIX PRA-.