参考范文：
The diagrams illustrate the way in which cement is made and how it is then used in the process of making concrete. Overall, limestone and clay pass through four stages before being bagged ready for use as cement which then accounts for 15% of the four materials used to produce concrete. While the process of making cement uses a number of tools, the production of concrete requires only a concrete mixer.
In the first stage of making cement, limestone and clay are crushed together to form a powder. This powder is then combined in a mixer before passing into a rotating heater which has constant heat applied at one end of the tube. The resulting mixture is ground in order to produce cement. The final product is afterwards put into bags ready to be used.
Regarding the second diagram, concrete consists of mainly gravel, which is small stones, and this makes up 50% of the ingredients. The other materials used are sand (25%), cement (15%) and water (10%). These are all poured into a concrete mixer which continually rotates to combine the materials and ultimately produces concrete.(187)
