The diagrams explain the processes of producing cement and concrete.(mọi người cho mik hỏi1. sau must +v nguyên thể vậy tại sao lại chuyển thành be made)
Overall, there are five stages for making the cement and one for the concrete. The cement must 1__be made_____ (to make) first, as it 2___________ (to use) to make the concrete.
To make cement, firstly limestone and clay 3________ (to feed) into two rollers which 4_________ (to crush) them up into a powder. This power 5__________ (to mix - then) together, before 6_________ (to travel) down a tube and into a rotating heater.
The heat comes up from the bottom as the heater rotates, and once the power is ready, it 7________ (to emerge) from this machine onto a conveyor belt where it 8___________ (to grind - then) into the cement. Finally it 9_________ (to separate) into bags.
This cement is then used to produce the concrete. To do this, there is a mixture of 15 per cent cement, 10 percent water, 25 percent sand and 50 percent gravel. These 10__________ (to place) into a concrete mixer, which spins in order to form the concrete
1. be made
2. is used
3. are fed
4. crush
5. is then mixed
6. travelling
7. emerges
8. is then ground
9. is separated
10. are placed
