题型:问答题 简答题 Glad to see you back. How long _____ in Russia? [ ]A. did you stay B. have you stayed C. were you staying D. have you been staying 查看答案
题型:问答题 简答题 关于神经元的膜电位,正确的是()。A.细胞外-60~-90mVB.细胞内-60~-90mVC.细胞内-90~-200mVD.去激化后细胞内50~90mVE.去激化后细胞内0~90mV 查看答案