879.Unfortunately, when 1 got to her flat, she __________，so we had only time for a few words.

A.just left

B.had just left

C.has just left

D.was just leaving

880.Mr.White works with an import and export company,bu he __________ for this industrial fair,since he is on leave.

A.has worked

B.works

C.has been working

D.is working

879.答案是D;

根据语境，我到达时她正要离开。

880.答案是D;

此题指眼下正在此地帮忙。