如果帮助客户Swiftie扫地机器人规划关键词，以下哪一组关键词全部都可以被归类为通用词？ A: MRobot, Kovacs, Bobsweep, Li vacuum B: robot vacuum, smart vacuum, robotic vacuum C: Swiftie smart vacuum, how to buy Swiftie, Swiftie deals D: 以上三项全部都是

Which of the following titles best describes the passage as a whole A: The Vacuum: Its Fluctuations and Decay. B: The Vacuum: Its Creation and Instability. C: The Vacuum: A state of Absence. D: Particles That materialize in the Vacuum.

vacuum<br/>tube ______

The vacuum cleaner is a valuable labor-saving ______.

The fluid cannot reach a complete vacuum state.

The hypothetical state of drawing small molecules by software is A: Vacuum gas phase B: Atmospheric liquid phase C: Atmospheric solid phase D: Vacuum solid phase

The crankcases of many diesel engines are kept under a slight vacuum to （）

Why did the Walt Disney Company suffer from the leadership vacuum?

It has 2 walls: the inner and the outer. ______ these walls, there is a vacuum to keep the liquid at a constant temperature.

4-2。which is the best material for heat insulation？（ ） A: water B: cotton C: vacuum