"Если" is a general way to say "if". Если А, то В. = If A, then B. Если будет хорошая погода, мы пойдем гулять. = If the weather is nice, we'll go for a walk. Если ты не против. = If you're ok with it. "Если бы" is used for past tense or subjunctive mood. Если бы я знал! = If only I knew! Если бы я его увидел, то сказал бы тебе. = If I saw him, I would tell you. Если бы ты позвонил, я бы пришел. = If you had called me, I would have come. "Ли" is closer to "whether". Я не знаю, придет ли он. = I don't know if he will come. / I don't know whether he will come.

1) Victor doesn't know if (whether) he will go to the movie theater. There is not condition in the sentence. It is more like possibility to do something, it doesn't depend on anything. Another example. I am not sure if she can read (Я не уверен, умеет ЛИ она читать). 2) I will buy tickets, if he goes to the movie theater. It is the "First Condition". It depends on availability of tickets. He will go to the movie theater under the condition.

I need to the difference between если, если бы и ли and when we use each word?

Ли - whether, if Если - if

Добрый день. В чем ваш вопрос? Если он о том, правильно ли построены предложения - да, правильно, только не "ог", а "он" (но думаю, это опечатка).