Complex sentence: Like most playwrights of his period, William Shakespeare did not always write alone and a number of his plays are collaborative, or were revised after their original composition, although the exact number is open to debate.
Split into simpler sentences: Like most playwrights of his period, William Shakespeare did not always write alone. A number of his surviving plays are collaborative, or were revised by others after their original composition, although the exact number is open to debate.