The first diagram (31-illustrate)____________the process of cement manufacture, and the second diagram (32-show)_____________ the materials that go into the production of concrete.
 
It is clear that there are five stages in the production of cement, beginning with the input of raw materials and ending with bags of the finished product. To produce concrete, four different materials (33-mix)______________ together.
 
At the first stage in the production of cement, limestone and clay (34-crush)____________ to form a powder. This powder then (35-mix)______________ before it passes into a rotating heater. After heating, the resulting mixture (36-grind)_______________, and cement (37-produce)______________. Finally, the cement (38-package)_______________in large bags.