听力原文：The order for 100 pairs of blue trousers is proving difficult to meet for we're o

ut of stock of that particular shade. We do have black.

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A．We're going to run out of stock of blue trousers, though we do have black trousers.

B．Black cannot be used to replace the material for this order of trousers.

C．In order to get this shade of trousers, we had to meet the stock-keeper, otherwise we had to use black as substitute.

D．We had to exchange the black shade of cloth for blue one so as to meet the order.