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