24、

They did not seem to realize what the poison of Nazism was doing to them. 
A. They did not seem to realize the great harm that Nazism was doing to them.
B. They did not seem to realize the great harm that poisonous gas developed by Nazism..
C. They did not seem to realize what kind of poisonous gas Nazists were developing.
D. They did not seem to realize that the Nazusts weere developing a kind of poisonous gas.