修一段路，第一天修全路的1/2还多2千米，第二天修余下的1/2还少1千米，还剩下20千米没有修完。公路的全长是（    ）千米。

If you can''t dig into the field you have chosen for your pursuit, it is hardly possible for you to achieve anything significant in the field.

A．acquire

B．require

C．accompany

D．accomplish