- She wrinkled her brows in concentration .
- S is the concentration of unpaired nucleotides .
- Freckles are simply concentrations of melanin .
- This concentration is not dissipated by agents .
- Some of the concentrations are negligibly small .
- strengthening the concentration (as of a solute in a mixture) by removing diluting material
- bringing together military forces
- great and constant diligence and attention
- the strength of a solution; number of molecules of a substance in a given volume
- the spatial property of being crowded together
同義詞：density, denseness, tightness, compactness
- complete attention; intense mental effort
同義詞：engrossment, absorption, immersion
- increase in density