actual selected unit的用法和样例：
- She was experimenting in selected units.
- A phase A fundamental positive sequence voltage selected unit based on LPF substitutes for the original ip-iq PLL to ensure exact voltage of A phase is selected even in case of imbalance three phase voltage.
- Eisenhower had approved a final list of acceptable running mates and then turned the actual selection over his inner circle of advisers.
- George Washington actually selected the site for The White House and directed its construction,yet he is the only president not to have lived there.