How do you plan to solve it?
module t_ff_async_pr ( input CLK, input RST, input PRE, input T, output reg Q ); always @(posedge CLK, posedge RST, posedge PRE) begin if (RST) Q <= 1'b0; else if(PRE) Q <= 1'b1; else Q <= T ? ~Q : Q; end endmodule