问题
选择题
Just as sound travels through the air in waves, electricity travels through the air in ______ radio waves.
A．what is called
B．which is called
C．what it is called
D．which it is called
答案
答案：A
本题考查名词性从句。介词in后面的宾语从句中缺少主语，故用what做主语，故选A。