Please turn to Page twelve and look at fifth picture.这里的 fifth picture前为什么不用定冠词?

Please turn to Page twelve and look at fifth picture.这里的 fifth picture前为什么不用定冠词?
Please turn to Page twelve and look at fifth picture.
这里的 fifth picture前为什么不用定冠词?

Please turn to Page twelve and look at fifth picture.这里的 fifth picture前为什么不用定冠词?
不用 定冠词 the 错了.
fifth 是序数词,前面应该加 定冠词the .