St. Mary’s Clinic, which is in the compound of the Sts. Peter and Paul Cathedral in the Mongolian capital had been closed since April for the building of a new extension.
自今年四月份以来，位于蒙古首都圣伯多禄圣保禄主教座堂庭院的圣玛利诊所，因进行扩建而暂时关闭。
2
Slot milling with flat parts of the closed contour, the cut can not cut out part of the extension.
铣削平面零件内槽的封闭轮廓时，切入切出不能有外延部分。
3
It is proved that relative hereditary, relative closed transition, weak homeomorphic invariant, L-good extension are all valid.