1. Some American banks (b) and companies (b) conduct transactions (b) over the Internet.
2. Mr. Hall delivers lectures (a) to the students (b) of a technical college.
3. Over the centuries (b) man’s (c) way of life was changed by a relatively small number of discoveries (b) and inventions (b).
4. Many applications (b) are under investigation in laboratories (b).
5. A computer system consists (a) of a number of different units (b).