So small ______ that the most powerful microscopes cannot detect them.
A: are these particles
B: B. were these particles
C: these particles are
D: D. these particles were
A: are these particles
B: B. were these particles
C: these particles are
D: D. these particles were
举一反三
- So small () that the most powerful microscopes cannot detect them. A: are these particles B: were these particles C: these particles are D: these particles were
- 下列穿透能力最强的粒子是（ ）？ A: β-particles B: α-particles C: Microwave D: X-ray
- The function of coalescer in the 2nd chamber is to ______. A: Allow small particles of oil to coagulate B: Allow larger particles of oil to escape C: Prevent clogged strainer D: Prevent the damage of fine filter
- The amount of scattering that occurs depends on the ( ). A: Size of particles B: Radiation wavelength C: Quantity of particles D: How deep the energy passes through the atmosphere
- Which of the following is the bulk volume of the powder？ A: True volume B: Void volume between particles C: Void volume in particles D: The sum of the above three