Engagement refers to：
A: occipital bone enters pelvic inlet plane
B: parietal bone enters pelvic inlet plane
C: biparietal diameter enters pelvic inlet plane
D: biparietal diameter enters the plane of ischial spine
A: occipital bone enters pelvic inlet plane
B: parietal bone enters pelvic inlet plane
C: biparietal diameter enters pelvic inlet plane
D: biparietal diameter enters the plane of ischial spine
举一反三
- Let's go to Paris _____________. A: by plane B: by a plane C: a plane D: by the plane
- “Board the plane” means _________. A: go out of the plane B: leave the plane C: enter the plane D: run away
- “Board the plane” means _________ A: go out of the plane B: leave the plane C: enter the plane D: run away from the plane. E: C
- 以下哪些是边界条件（ ）： A: mass inlet B: velocity inlet C: outflow D: pressure inlet
- 以下哪些是边界条件（ ）： A: velocity inlet B: outflow C: pressure inlet D: mass inlet