519.So far we have done a lot to build a low-carbon economy,but it is _______ ideal.We have to work still harder.
A.next to
B.far from
C.out of
D.due to
520.We give dogs time,space and love we can spare,and ________,dogs give us their all.
A.in all
B.in fact
C.in short
D.in return
519.答案是B;far from远非；next to仅次于；due to因为，由于。根据句意，我们所做的离理想中的要求还差很远，仍需努力。
520.答案是D;in all 总计，总之；in fact 事实上；in short 简而言之；in return 作为回报。
