Past tenses of Neoslavonic verbs are very easy and regular. There is only one pattern for all verbs (except only 3 irregular verbs). This pattern is simply based on the infinitive.
Neoslavonic (as well as spoken Slavic) operate past tenses with so called L-participle. It is a special form of indeclinable verbal adjective made from the infinitive.
diela-ti → diela-l, diela-la, diela-lo, diela-li (to do)
pisa-ti → pisa-l, pisa-la, pisa-lo, pisa-li (to write)
vidie-ti → vidie-l, vidie-la, vidie-lo, vidie-li (to see)
peč-ti → pek-l, pek-la, pek-lo, pek-li (to bake)
mož-ti → mog-l, mog-la, mog-lo, mog-li (to can)
simple past tense
The simple past tense is made in a very similar way as the L-participle.
diela-ti → diela-h, diela-še, diela-še, diela-hom, diela-ste, diela-hu (to do)
pisa-ti → pisa-h, pisa-še, pisa-še, pisa-hom, pisa-ste, pisa-hu (to write)
peč-ti → peč-e-h, peč-e-še, peč-e-še, peč-e-hom, peč-e-ste, peč-e-hu (to bake)
This simple past tense is very similar to the past tenses in Croatian, Serbian, Montenegrin, (Slavo)Macedonian and Bulgarian. But they are almost unfamiliar in the western Slavic and eastern Slavic languages.
composed past tense = prior present tense
As written above, the western Slavic and eastern Slavic languages do not use the simple past tense (-hu, -še , ...). Instead of it, they use the composed past tense made by the combination of the verb byti (to be) in the present tense and the L-participle in corresponding personal form (m. or f. or n. or pl.).
Jesi li pisala pismo? Did You (f.) write a letter?
Ne, on je pisal to pismo. No, he did write this letter.
If You use past form of the verb byti (to be) instead of the present form, You create the prior past tense.
Bieše li pisala pismo? Had You (f.) wrote a letter?
Ne, on bieše pisal to pismo. No, he had wrote this letter.
symmetric system of Neoslavonic present and past tenses
If we do not assume a simplified system with only one past tense (either simple or composed), we can define the complex symmetric system of four tenses in two time levels: the present level and the past level.
example of the present time level:
Hvalime Vas, že jeste razdielili otpad. Thank you for sorting waste. - thanking = present, sorting = prior-present.
the same example moved to the past time level:
Hvalihom Vas, že bieste razdielili otpad. We did thank you for sorting waste. - thanking = past, sorting = prior-past.
It is obvious, that the relationship between thanking and sorting is the same in both examples: Sorting first, thanking after.