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 or posedge RST or posedge PRE) begin if (RST) Q = 1'b0; else if (PRE) Q = 1'b1; else if (T) Q = ~Q; else Q = Q; end endmodule