An user Portuguese
says…

Se
Subordinating conjunction
  não
🚫
Adverb
  o
Pronoun
  fizerem
Verb
será
Auxiliary
  entendido
Verb
  que
Subordinating conjunction
  eles
Pronoun
  escolhem
Verb
  fazer
Verb
  os
Determiner
  exercícios
Noun
  em
Adposition
  espanhol
espanhol
Noun
.

If they do not, it will be understood that they choose to do the exercises in Spanish.
Collections
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New
Letters and language
Words and sentences
New
fizerem

third-person plural future subjunctive of fazer

New
entendido

past participle of entender

New
eles

New
escolhem

third-person plural present indicative of escolher

New
fazer

  1. to make
  2. to make
  3. to make
  4. to make
  5. to make
  6. to play; to pretend to be
  7. to turn; to reach an age; to have a birthday
  8. to sell (something) [with por ‘for a given price’] (usually to make cheaper in a bargain)
  9. to attend a course (academic or not)
  10. to pass (said of time)
  11. to be; to occur (said of a weather phenomenon)

New
exercícios

plural of exercício

New
em

  1. in; inside; within (contained by)
  2. on; on top of (located just above the surface of)
  3. in; at (located in a location)
  4. in (part of; a member of)
  5. in; into; inside (towards the inside of)
  6. indicates the target of an action
  7. in (pertaining to the particular thing)
  8. in (immediately after a period of time)
  9. in; during (within a period of time)
  10. at; in (in a state of)
  11. in (indicates means, medium, format, genre or instrumentality)
  12. in (indicates a language, script, tone etc. of writing, speaking etc.)
  13. in (wearing)
  14. (slang) indicates that the object deserves a given punishment

espanhol
New
espanhol

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