They _____ on the program for almost one week before I joined them, and now we _____ it as no good results have come out.

A．had been working; are still working

B．had worked; were still working

C．have been working; have worked

D．have worked; are still working

6～7岁的儿童的力平均为（）

A.10kg

B.15kg

C.20kg

D.25kg

E.30kg