薄荷油中的主要化学成分是()
A.(-)薄荷醇
B.(+)薄荷醇
C.(-)新薄荷醇
D.(+)异薄荷醇
E.(-)新异薄荷醇
参考答案:A
第二产程宫缩期间宫腔内压力可达
A.25~30mmHg
B.40~60mmHg
C.50~80mmHg
D.70~100mmHg
E.100~150mmHg
Establishing business relationship with prospective customers is very important for both new and established.