观测水平角时为什么要盘左盘右观测？
参考答案：
观测水平角时采用盘左盘右观测，可以消除照准差.
My friend, Jack, will have a holiday as soon as he ________ his work next week.
A．finishes
B．will finish
C．finished
D．finish
下列哪项是深反射
A．腹壁反射B．桡骨骨膜反射C．角膜反射D．提睾反射E．肛门反射
