The Conditional Mood

is expressed by the verb ending -us — used for anything hypothetical ("would", "were to"):

• mi kredus – I would believe, I should think
• Se mi estus sana, mi estus tre feliĉa. – If I were well, I would be very happy.

⚠️ Watch out: both halves of the sentence take -us (the "if" clause and the main clause) — unlike English, which mixes "were" and "would".

💡 Memory aid: that completes the verb system — -i (infinitive), -as / -is / -os (the three tenses), -u (command), -us (conditional). Six endings cover every verb.

Kvazaŭ

is used as a conjunction, normally followed by the conditional:

• Vi sidas tie kvazaŭ vi estus riĉulo. – You are sitting there as if you were a wealthy man.

It can also be used elliptically:

• Vi sidas tie kvazaŭ riĉulo. – You are sitting there as if (you were) rich.

The Suffix -ad

makes a noun from a verb, naming the action itself:

• kanti (to sing) → kantado – (the act of) singing
• suferi (to suffer) → suferado – suffering

It also conveys continued or repeated action:

• rigardi (to look) → rigardadi – to go on looking, to gaze
• demandi (to ask) → demandadi – to keep asking questions
• informo (information) → informado – publicity

The Suffix -ar

indicates a collection of objects viewed as a whole:

• arbo (tree) → arbaro – wood, forest
• vagono (coach) → vagonaro – train
• vorto (word) → vortaro – dictionary

💡 Memory aid: -ar bundles individual items into a set:

• arbo (tree) → arbaro (forest)

The Suffix -um

is a joker suffix, with no fixed meaning:

• plena (full) → plenumi – to fulfil
• proksima (close) → proksimume – approximately
• suno (sun) → sunumi – to sunbathe
• malvarmumi – to catch a cold

💡 Tip: -um is the joker among suffixes, just as je (lesson 6) is the joker among prepositions — learn each -um word individually.