---Oh, doctor, the wound on my leg is infected.

---You really shouldn’t have left it _______ to the sun.

A．discovered

B．exposed

C．opened

D．buried

根据我国《海关法》的规定，在进口环节由海关代征增值税。计算进口增值税的公式为：(关税完税价格+关税额+消费税额)×增值税率( )