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Ĉu la flago estas ruĝa aŭ blua؟

"Ĉu la flago estas ruĝa aŭ blua؟" - "Is the flag blue or red?". Why is "estas" in the sentence, why is it required? Why can it be "Ĉu la flago ruĝa aŭ blua?"?

January 16, 2018



"Ĉu" comes from Polish "czy" and means "whether or not".

"Ĉu la flago estas ruĝa aŭ blua؟" - (whether or not) is the flag red or blue?

In contrast:

"Ĉu la flago ruĝa aŭ blua؟" - (whether or not) flag red or blue?

The second sentence doesn't make much sense, because "Ĉu" needs some kind of reference, a verb.

It's: Ĉu (whether or not) + is/become/other verb or action + quality/state/object ?

Example: Ĉu vi scias/parolas Esperanton? - (Whether or not) do you know/speak Esperanto?

Ĉu vi Esperanton? - (whether or not) you Esperanto? - that sentence doesn't have a logical translation and sounds like broken English.

The "Ĉu" (czy) concept is a bit hard to explain, the "whether or not" is probably the closest to an accurate translation of it's meaning. That's just my humble opinion about it from a Polish native speakers' point of view ;)

January 16, 2018



January 16, 2018


I suspect the point of confusion here is that you're seeing "Ĉu" as "is". Instead, it indicates that what is to follow (usually a statement grammatically) is a closed question (yes/no).

  • Vi havas fraton - you have a brother
  • Ĉu vi havas fraton? - do you have a brother?
  • Lia nomo estas Karlo - His name is Karlo
  • Ĉu lia nomo estas Karlo? - Is his name Karlo
January 16, 2018


Thank you very much, sir!

January 16, 2018


It's the 'IS' in the question.

Take the 'IS'es out of your questions,

'Why "estas? in the sentence, why it required?'

and they seem odd, yes?

The 'Ĉu' acts to make the statement a question, rather than how English changes the word order:

La flago estas ruĝa aŭ blua. = The flag is red or blue.

Ĉu la flago estas ruĝa aŭ blua? = Is the flag red or blue?

January 16, 2018


"Ĉu" can be thought of as quite similar to the "¿" in Spanish, or "do" in English. It signals that the rest of the phrase will be a question. It is perhaps more similar to "do" because the "¿" can be used in non yes-or-no questions, but whatever helps understand is useful.

January 18, 2018
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