ability to focus的用法和样例：
- From a very young age he had an extraordinary ability to focus.
- Presbyopia, or the loss of ability to focus on close objects, affects almost everyone.
- This measured the breadth of their isual attention and ability to focus on what was in front of them.
- Adult Golden Retrievers love to work, and have a keen ability to focus on a given task.
- Both types impede development of a child's ability to focus the eyes and merge images from the two retinas into one (fusional reflex).