plant maintenance的用法和樣例：
例句
- The applicant for a patent for invention shall pay the application maintenance fee for all the years,with the exception of the year in which the patent right is granted.
發明專利申請人應當一併繳納各個年度的申請維持費，授予專利權的當年不包括在內。 - He took a course to learn about car maintenance.
他學習了汽車保養的課程。 - The machinery requires constant maintenance.
這些機器需要經常保養維修。
