 |
| English | Chinese |
| B class of utilization of mechanisms | 结构件利用等级 |
| B size hole | B型孔孔径约 60 mm/2. 3 in. |
| Ordovician period system B | 奥陶纪系 |
|
| English | Chinese |
| B class of utilization of mechanisms | 结构件利用等级 |
| B size hole | B型孔孔径约 60 mm/2. 3 in. |
| Ordovician period system B | 奥陶纪系 |