计算：（-a）2•（-a3）•（-a）+（-a2）3-（-a3）2．
原式=a2+3+1+（-a2×3）-a3×2
=a6-a6-a6
=-a6．
______, they make mistakes as part of their everyday behavior. [ ]
A. Not only humans make mistakes
B. Not only do humans make mistakes
C. Only humans make mistakes
D. Only do humans make mistakes
期货公司许可证正本遗失的，期货公司应于（）日内在中国证监会指定的报刊或者媒体上声明作废，并持登载声明向中国证监会重新申领。
A．10
B．15
C．20
D．30
