21.---The * is trying to protect the giant pandas.---I konw.By 2020,they___about69500 square miles of land to the country's nature reserve system.A.add B.are adding C.will add D.will have add

问题描述:

21.---The * is trying to protect the giant pandas.---I konw.By 2020,they___about
69500 square miles of land to the country's nature reserve system.
A.add B.are adding C.will add D.will have add

D