Отметьте правильные и исправьте неправильные предложения. 1. Two years ago, we have seen big increases in the price of oil. 2. The price fell in the last two days and it is now 5 per cent lower than before. 3. Our competitors reduced their prices in January. 4. We didn’t raise our prices in recent weeks: they are still at the same level as they were two months ago. 5. Have you received your prices recently? 6. We have reviewed our prices in March.