"No, they are not tall."

[Arcvelox]

If the gender is not known, which gender do you use? Didn't this example use masculine, animated, plural nominative?

[VladaFu]

You can use any gender you want. In real use it will depend on the context. The translation above does use animate masculine and the adjective is in the nominative case.

[openminded2]

I put "Ne, oni nejsou vysoka." and it said it was wrong and should have been "Ne, ona nejsou vysoká." Soooo, how is oni wrong? and vysoká is only for...?plural feminine?

[VladaFu]

oni is masculine
animate

vysoká is either feminine singular or neuter plural (cf. with eg. Latin)

You should be able to check that yourself in the Tips and notes.

[openminded2]

I have no idea how to find "Tips and Notes". Nothing comes up in the Help.

[VladaFu]

On the web click on the lightbulb icon when choosing the skill.

[Alice805457]

When you first start a lesson, the little box which says what lesson you are on has two icons. One is a key, and the other is a lightbulb. Select the lightbulb for Tips and Notes. I had to ask, also! Unfortunately, this only displays in Duolingo on the web, not in the mobile application.

[Emily-Smiley]

Why can't use "Ne, oni nejsou vysoke?"
If the thing is masculine inanimate?

[VladaFu]

The masculine inanimate pronoun is ONY.

[Emily-Smiley]

thank you ;-)

[Ahmed372441]

ne, to nejsou vysoká. why is it wrong?

[VladaFu]

The same as your last question. https://forum.duolingo.com/comment/24434260

[Ahmed372441]

oh sorry i forgot, but this to je/ je to pattern is kinda confusing sometimes