1. Two years ago, we saw 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. - верно
3. Our competitors reduced their prices in January. - верно
4. We haven’t raised 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? - верно
6. We reviewed our prices in March.