第4题: [单项选择]酶原颗粒主要见于() A. 浆液性腺泡细胞 B. 黏液性腺泡细胞 C. 肌上皮细胞 D. 闰管细胞 E. 分泌管细胞 参考答案:A 答案解析:试题难度:中;此题为涎腺组织结构基本知识题,考查对各种涎腺细胞结构韵知谢浆液性腺泡在光镜下,细胞呈锥体形,基底部较宽,紧附于基底膜上,顶端向着腔内。胞核为圆形,位于基底部1/3处。胞质色深,组织固定好
A. should have died B. must be dying C. must have died D. ought to die 参考答案:C 答案解析:must have done用来表示对过去某动作的肯定推测,作“肯定,一定是”讲,例如:He must have been to England for he knows so much about