21+i=2(1-i)(1+i)(1-i)=1-i
故答案为:1-i.
It took __________ building supplies to construct these energy-saving houses. It took brains, too. [ ]
A. other than
B. more than
C. rather than
D. less than
保安服务操作应按照国家()规定进行。
A.法律
B.法规
C.规章
D.制度
E.法令