With more and more farmers moving to cities, an inadequate labor force is becoming a major factor affecting the country's grain output.
Despite their______ of interest,Fleming kept trying to develop the chemical ______ it would be safe and effective.
Helen always helps her mother even though going to school ______ most of her day.
We regret to inform you that there are no tickets ______ for Friday's performance.
Mr.Wang ______ two boys to send the sick boy to the nearest hospital.
My teacher's rich knowledge of science ______ my decision ______ study science.