Hi everyone! Good news. A book sale.____will people drive cars in space? Will you meet traffic ____? You'll get answers from our books. Are ____ interesting for you? They can do heavy work. You ____enjoy short working hours. We've got some storybooks about them. What's the best way to buy products at very good prices? Our books will tell you something about online ____? 

    Welcome to the playground this Saturday.

    Have a nice day!

如图，点A在双曲线上，且OA＝4，过A作AC⊥轴，垂足为C，OA的垂直平分线交OC于B，则△ABC的周长为 (        )