feed per stroke的用法和样例：
- Radial feed per stroke of cutter (stepless)
- If yes, how much is the subscription fee per year?
- How much is the guide fee per day?
- For every tenth added in streamline you can subtract a tenth per stroke in overall time!
- Calves swimming in echelon showed a 28% increase in average swim speed and a 19% increase in distance per stroke.