Why 'je to mys' and not 'je mys'. I thought 'to' was demonstrative, ie that the.
Czech sentences in 90% a subject. In this sentence "to" is not demonstrative pronoun (the, that) but subject (it).
Why not “Ta je mys”?
You wil see that "Je to..." and "To je..." is a very common type of sentence. It is always TO for all genders in singular and plural. The to dentes something indeterminate what you determine morw closly in the sentence.
I thought myš is feminine so it should be "ta myš". but my answer is incorrect (je ta myš). please enlighten me
Just read above.