【单选题】重度子痫前期孕妇于孕晚期出现腹痛伴有阴道流血,最可能的疾病是( )
【单选题】According to the passage, which of the following was an obstacle to the development of the icebox?
A.
Competition among the owners of refrigerated freight cars.
B.
The lack of a network for the distribution of ice.
C.
The use of insufficient insulation.
D.
Inadequate understanding of physics.
【单选题】为了探讨不同训练方法对提高耐力素质的效果,现将48名基本条件相似的男生随机分成3组,进行不同方法的训练,用1500米成绩反映训练效果。请问因素是( )。
【单选题】According to the passage, which of the following posed the biggest obstacle to the development of military forts?
B.
Shortage of materials.
C.
Attacks by wild animals.