It had been proved that corn and potatoes have high nutritional value.
举一反三
- Shark Fin and Swallow Nest have extraordinary nutritional value.
- The old methods have ____the best of all. A: been proved being B: been proved to be C: proved being D: proved as
- Cut out_____ foods high in fat and sugar and low in nutritional value, such as snack foods,soda, and fast food.
- Their efforts to improve the corn production have been very (effect)______.
- The millions of calculations involved, ____by hand, would have lost all practical value by the time they were finished. A: had they been done B: they had been done C: having been done D: they were done