问题
单项选择题
下列全由矿物组成的一组是（）
A、石英、玛瑙、煤、云母；
B、辉石、沥青、石油、金刚石；
C、人造水晶、矿泉水、长石、方解石；
D、高岭石、石英晶簇、花岗斑岩中的长石斑晶
答案
参考答案：D
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下列全由矿物组成的一组是（）
A、石英、玛瑙、煤、云母；
B、辉石、沥青、石油、金刚石；
C、人造水晶、矿泉水、长石、方解石；
D、高岭石、石英晶簇、花岗斑岩中的长石斑晶
参考答案：D
| Artificial flowers are used for scientific as Well as for decorative purposes. They are made from (51) of materials, such as wax and glass, so skillfully that they can scarcely be (52) from natural flowers. In making such models, painstaking skill and artistry are called for, (53) thorough knowledge of plant structure. The (54) of glass flowers in the Botanical Museum of Harvard University is the most famous in North America and is widely known (55) the scientific world. (56) , there are several thousand models in colored glass, the work of two artist naturalists, Leopold Blalschka and his son Rudolph. The intention was to have the collection (57) at least one member of each flower family native to the United States. (58) it was never completed, it contains more than seven hundred species representing 164 families of flowering plants. (59) detail of these is accurately reproduced in color and structure. The models are (60) n locked cases as they are too valuable and fragile for classroom use. |
A．concentration
B．gathering
C．collection
D．assembly