About pokazivati and pokazati, you are right. About your sentences: 1. Your sentence absolutely can pass but correct form is: Ne znam pokazuje li joj knjige. 2. Correct. Now, I assume you'll be asking why is "je" ommited in first sentence. The difference between first and second sentence is tense. While first is in present form, second one is in past and we form past tense with present form of verb "biti" (to be) and main verb in correct form. Present form of verb "biti" is: sam (for I) si (for you) je (for he/she/it) smo (for we) ste (for you - more persons and for polite form singular) su (for they) Those above words are short forms of verb "biti". Longer forms are: jesam / jesi / je/ jesmo / jeste/ jesu For past tense main verbs end with: singular: -o/ao (masculine), -la (feminime), -lo (neutral) plural: -li (masculine), -le (feminime), -la (neutral) Of yourse, there are some exceptions :) And some examples for making my answer more understandable (about "je"): Am I here? - JESAM li ovdje? Does this work? - Radi li ovo? (here you do not have present form of "biti") Does it rain? - Pada li kiša? Did you sleep well? - JESI* li spavAO dobro? --> past tense * when you ask questions (when verb "biti" is at the beggining of question), you should use longer version If you need more explanation, just ask.

Yes Shawn... Pokazivati - it is used for something that is not finished. Pokazati - It means that the action is finished. 1. Ne znam da li joj je pokazIVAO knjige. 2. Ne znam da li joj je pokazaO knjigu. In Croatian, it is more common to say "Ne znam je li .... " I hope this helps. Please, let me know if you have any further questions. Have a nice day.