II. Listening Skills Making Calculations 1. W: It sounds expensive. Why did they charge you so much for repairing the computer? M: Well, its $25 for labor to start with. A new modern cost another 50 bucks. On top of that I needed a new battery, and it cost $17
斑岩铜矿( Porphyry copper deposits)为世界提供了50%以上的 铜金属( over 100 producing mines)。 Their close relatives the porphyry moly deposits produce 70%o of the world's moly. Both deposit types will be discussed separately, but they share many characteristics and are formed in somewhat similar manners