It’s difficult to ___ these old books for some of them ______ none of the classification.
What people like to eat is subjective, but ______ the northerners like dumplings while the southerners are fond of rice.
Your are ______ to suffer from bad health if you keep smoking.
Nuclear science should be developed to benefit people _______ harm them.
This problem may _______ more serious ones if left unsolved.
Crops such as peas or soybeans put important minerals back into the soil, ______ it ready for crops that need fertile soil.