MATLAB为什么不显示子图title

MATLAB为什么不显示子图title源代码如下：求更改建议及不显示原因t=0:0.1:10;x=sin(t);subplot(2,2,1);N=1;title('N=1')y=sin(N*t+3);plot(x,y,'--r','LineWidth',2)grid on%加网格subplot(2,2,2);N=2;title('N=2')y=sin(N*t+3);plot(x,y,'-.b','LineWidth',2.5)grid on%加网格subplot(2,2,3);N=3;title('N=3')y=sin(N*t+3);plot(x,y,':y','LineWidth',3)grid on%加网格subplot(2,2,4);N=4;title('N=4')y=sin(N*t+3);plot(x,y,'--r','LineWidth',2)grid on%加网格