(x3)2÷[x3•______÷x2]=1.
∵(x3)2÷[x3•xa÷x2]=1,即x6÷x3+a-2=1
∴3+a-2=6,解得a=5,
∴空格处为:x5.
故答案为:x5.
My father will be back May.
A.in
B.at
C.on
D.from
钻进过程发现异常该怎么办?