这个清洗系统采用两阶段设计，先用冷水预洗，再用热水深度清洁。

The cleaning system uses a ___two-phase design, first pre-washing with cold water and then deep cleaning with hot water.

这台老式电风扇需要两相电源才能正常工作。

This vintage electric fan requires a ___two-phase power supply to operate properly.