∵(1+2i)2=1+4i+4i2=-3+4i
∴(1+2i)23-4i=-3+4i3-4i=-(3-4i)3-4i=-1
故答案为:-1
The farmer was very thankful to the doctor ______ treated his son.
A.what
B.which
C.who
D.whose
差别化纤维有哪些特殊功能?