a period of probation的用法和样例：
- After a period of probation he was appointed to the staff.
- It is a period of probation during which their work will be closely monitored.
- Childhood is a period of rapid growth.
- The capital cost is amortizable over a period of ten years.
- The new government ushered in a period of prosperity.
- The lectureship is tenable for a period of three years.