________ he is ,he seldom shows his precious coins to others.

A．Coin -collector as

B．As a coin –collector

C．A coin- collector as

D．Coin- collector that

铁矿石整粒的首要目的是使从矿山来的矿石达到（）的要求，以改善高炉冶炼的气体力学和还原条件。