Absence of symptoms的用法和样例：
- Low PH value of initial blood gas, early onset of symptoms at birth and total absence of hemidiaphragm were the three most poor prognostic factors (P<0.01).
- The absence of color in that drawing make it dull.
- We are in the absence of experience.
- Absence of mind is altogether an involuntary thing.
- The absence of color in that drawing makes it dull.