Раскройте скобки, поставив глагол в нужное время.
1. Some years ago this product (be) an innovation.
2. We (apply) for a patent soon.
3. TV (invent) before a clock-television (appear).
4. A clock-television (appear) after TV (invent).
5. Market research usually (do) carefully.
6. Now we (modify) our small screen version.
7. A large scale producer (do) much testing before they (start) selling their new modification.