We have learned that instead in, at, on we use the -de locative case suffix. Of course this is an -e type suffix and has the -de and -da versions. But also it has the -te and -ta versions. 

The -te and -ta versions are used if the word ends with a voiceless consonant (p, ç, t, k, h, s, ş, f). This is called consonant harmony. 

Example:

parkta > in the park

Add the correct locative suffix according to vowel harmony and consonant harmony. The locative suffix can be -de, -da, -te, -ta.