Three other types of airspace, Classes D, C and B, govern the vicinity of airports.
其他三种领空，D、C 和 B 类，管理着机场周围地区。
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The known taxonomy types include NAICS, UNSPSC, SIC, or a geographic code (GEO); the known identifier types include D-U-N-S, Thomas Registry numbers, and US Tax ID.
These types of detectors are often called three-dimensional (3-d) detectors.A widely spaced hole-array is desirable in that it allows lateral depletion and charge collection.