Questions & Answers about Эта ваза хрупкая, поэтому не ставь её на край стола.
Because ваза is a feminine singular noun.
In Russian, demonstratives like this change to match the noun’s:
- gender
- number
- case
So in the nominative singular:
- этот = masculine
- эта = feminine
- это = neuter
Since ваза is feminine, you say эта ваза.
For the same reason: it agrees with ваза.
Хрупкий is the dictionary form of the adjective, usually given in the masculine singular nominative. But here it describes ваза, which is feminine singular, so it becomes:
- masculine: хрупкий
- feminine: хрупкая
- neuter: хрупкое
- plural: хрупкие
So эта ваза хрупкая means literally this vase fragile, with the adjective matching the feminine noun.