28. Укажите, какие предложения соответствуют содержанию текста.
Подтвердите свои ответы фактами из текста.
1. Anthracite coals may be divided into lignite and common
brown coal.
2. Coals are ranked according to the percentage of carbon they
contain.
3. Peat, with the least amount of carbon is the lowest rank, then
comes lignite or brown coal.
4. Brown coal is hard and it is not liable to spontaneous combus
tion.
5. Bituminous coal weathers rapidly and one cannot keep it in
open piles.
6. Being intensively used in the Iron and steel industry bitumi
nous coal varies from medium to high rank.
7. Anthracite or hard coal, the highest in percentage of carbon,
can be blended with bituminous grades of coal.