问答题 灵长类动物的_____仅在妊娠最早几周内对胚胎起保护作用，此后主要靠_____分泌的HCG维持妊娠。

多项选择题 为明确诊断,以下哪种检查方法对肾盂病变鉴别诊断有价值: ()

单项选择题 This film Schindler’s List has achieved a great success. It has won ______ Oscar Awards out of twelve nominations.