a reduction in numbers的用法和样例：
- A reduction in the number of students in a class.
- The present observation of the gynoecial development supports the viewpoint that the evolution of flower in Potamogeton involves a reduction in number of parts.
- A reduction in pace, force, or intensity; a slowdown.
- A reduction in value, amount, or degree.
- The development of the project was seriously impeded by a reduction in funds.