在视网膜的黄斑区光感受器主要是______,在周边区感受器主要是______。
参考答案:视锥细胞‖视杆细胞
胰十二指肠切除术后,持续胃肠减压2周,无排气,腹部无压痛,肠鸣音减弱,T波低平,考虑存在
A.低钾血症B.等渗性缺水C.高渗性缺水D.低渗性缺水
The book is so boring. It isn't worth _____. [ ]
A. to read
B. reading
C. to see
D. seeing