Complete the text with suitable prepositions. Email has brought (a) ——— a revolution (b) ——— modem communication. Messages can be transmitted (c) ——— one country to another (d) ——— seconds. It is far cheaper than telephone calls. Trade and commerce has become greatly dependent (e) ——— this speedy mode (f) ——— communication. It has, however, not reached everyone, especially (g) ——— developing countries (h) ours, as most people cannot afford (i) ——— have a personal computer. But even here, people have started using commercially operated email facilities (j) ——— important purposes.