发生在桑葚期即受精后3天内()
A.双卵双胎
B.单卵双胎,双羊膜囊、双绒毛膜
C.单羊膜囊双胎妊娠
D.联体儿
E.单卵双胎,双羊膜囊、单绒毛膜
参考答案:B
_____ her emotion, she buried her face in her hands. [ ]
A. Controlled
B. To control
C. Being controlled
D. Having controlled
输出的电功率与输入的电功率的比例数称为效率。