将函数$y=\sin \left(6x+\frac{\mathrm{\pi }}{4}\right)$的图像上各点的横坐标伸长到原来的3倍，再向右平移$\frac{\mathrm{\pi }}{8}$个单位，得到的函数的一个对称中心是   (      )

⑴What did you do last night?____                  A. I got there by bus.

⑵How tall are you?____                                   B. I'm 1.60 metres.

⑶How did you get there?____                         C. I went to the Great Wall.

⑷Where did you go last weekend?____          D. I hurt my leg.

⑸What happened to you yesterday?____       E. I watched TV.