为什么必须写begin--end

always@(posedge V_CLK)begin
    if(iMode)begin
        if(iCapture)begin
            h_blank_bak <= h_blank_bak;
        end
        else begin
            h_blank_bak<=dram_rclk_bak;
        end
    end
    else begin
        h_blank_bak <= h_blank;
    end
end

always@(posedge V_CLK)begin
    if(iMode)begin
        if(iCapture)begin
            h_blank_bak <= h_blank_bak;
        end
        else begin
            h_blank_bak<=dram_rclk_bak;
        end
    end
    h_blank_bak <= h_blank;
end

排除这个错误花费了24小时