题目

—When is Jay's concert? —It's _______ three o'clock ________ the afternoon of July 18th. A . at;in B . at;on C . on;in D . in;on 答案：B10．下列运箅正确的是（　　）A．a3•a2=a6B．（a3）2=a5C．a5+a5=a10D．3x2•（-2x2）=-6x4