土壤板结会影响植物的生长，主要原因是

A．植物缺少无机盐，影响生长

B．植物缺少水，影响光合作用

C．土壤中缺少氧气，影响根的呼吸作用

D．植物缺少水，影响蒸腾作用

-Did you punish him for that?

-Yes,but I don't think I ________.[ ]

A．should have done so        

B．need to have done so

C．should do that            

D．ought have done that