4. It (to be) six o'clock in the evening now. Victor(to do) his homework. His sister(to read) a book. His mother and grandmother(to talk).

It is six o'clock in the evening now. Victor is doing his homework. His sister is reading a book. His mother and grandmother are talking.

Объяснение: Здесь нужно использовать Present Continuous, так как речь идет о действиях, происходящих в данный момент ('now' - сейчас). Витя делает домашнее задание, сестра читает книгу, мать и бабушка разговаривают – все происходит сейчас.