1.The price_______ ,but I doubt whether it will remain so.
A.went down B.will go down
C.has gone down D.was going down
1.C 说话时价格已经降了，动作已经完成，而且降价肯定对现在甚至以后造成了影响。
2.—Hi,Tracy,you look tired.
—I am tired.I________ the windows all day.
A.cleaned B.had cleaned
C.have been cleaning D.have cleaned
