问题
选择题
The declaration____saving the rivers and giving people their traditional rights over them.
A．calls for
B．calls up
C．calls off
D．calls in
答案
答案：A
词组辨析题。A.calls for 要求 B. calls up 打电话 C. calls off 取消 D. calls in 拜访 句意：声明要求拯救河流并给人民对河流的权利。根据语境选A
Na2SiO3 + H2O
Fe3O4 + 4H2