病人，男性，46岁，脑外伤致深昏迷，护士对其行胃管插入术，插管至食管处时遇到阻力，此处距门齿的距离约为
A. 10cm
B. 15cm
C. 20cm
D. 25cm
E. 40cm
查看答案
在光栅中，单缝衍射所起的作用并不改变主极大明纹的位置，只影响各级主极大明纹间的光强分配。
A. 对
B. 错
光栅衍射中，将光栅垂直会聚透镜光轴方向做微小的平移，则衍射图形会随之移动。
A. 对
B. 错
Learning about the great news, she was_excited to calm down.
A. much too
B. too much
C. so much
D. very much
They are teachers and don't realize to start and run a company.
A. what it takes
B. what takes it
C. what they take
D. what take they
微信支付 
支付宝支付