Don't take _____ for granted that your parents should support you all your life .You should learn to be independent.

A．this

B．it

C．that

D．those

变态反应性接触性皮炎从初次接触致敏物到T细胞活化、增殖播散全身需（）天，而再次接触相同致敏物到炎症反应形成则只需（）小时。