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<=0; else if (PRE) Q<=1; else begin case(T) 1'b1:Q<=~Q; 1'b0:Q<=Q; endcase end end endmodule