Find out the main idea of each message below (1-6). Choose from the ideas a-f. There is one extra letter that you do not need. There is an example (g) at the beginning.
1 Your battery is now empty. Please can you recharge it?
2 Ask a crew member if you wish to use electronic equipment during the flight
3 Defend your PC from hackers and viruses. Download "Anti-Virus" now!
4 Electronic devices may not be used until the plane has come to a standstill.
5 There is an insufficient credit on your phone to make this call
6 Your computer may have been infected. Do you wish to remove this file now?
a) Your message has not been sent for technical reasons
b) You do not have enough money to telephone anybody
c) You can only use electronic equipment when the aircraft has stopped.
d) You can delete a possible virus from your PC immediately.
e) You can buy protection for your computer on-line.
f) Do not use laptops or phones without first checking with the staff
while on board.
g) There is not enough energy for you to use this device.

1)Building materials are divided into natural (natural) and artificial(Строительные материалы разделяют на природные (естественные) и искусственные)

2)Не смогу сказать.

3)metals are divided into two groups: ferrous and non-ferrous(металлы делятся на две группы: черные и цветные)

4)Ferrous metals are those that contain steel and iron.Non-ferrous metals do not contain steel or iron. This group of metals includes: aluminum and copper, Nickel and lead, zinc and tin, brass and gold, silver and platinum, as well as many others that do not contain iron.(Чёрными называются те металлы, которые содержат сталь и железо.Цветные металлы не содержат стали и железа. К данной группе металлов относятся: алюминий и медь, никель и свинец, цинк и олово, латунь и золото, серебро и платина, а так же многие другие, не содержащие железо.)

1) The properties of building and materials are classified into four groups: physical, mechanical, chemical, technological, etc.

2) Resistance to salt aggression and other chemicals (wood)

An important advantage of natural stone is strength, durability, resistance to environmental influences, frost resistance (stone)

Strength; reliability; versatility; combination with other materials (metal)

3) All metals are divided into two groups: ferrous and non-ferrous

4) Ferrous metals and alloys contain iron, non-ferrous metals do not. Ferrous metals are mild steel, carbon steel, stainless steel, cast iron and wrought iron. ... Since they do not contain iron, non-ferrous metals have a higher resistance to corrosion and rust.

Объяснение: just decided