If you walk around the city of Oxford, where we are today, and have a look at the brickwork, which I've enjoyed doing in the last couple of days, you'll actually see that a lot of it is made of limestone.
如果你走在如今的牛津城， 观察一下那些砖块—— 这些天我很喜欢这样—— 你能看见很多都是用石灰石做的。