在垂直角观测中,测得同一目标的盘左、盘右读数分别为92°47′30″、267°12′10″,求得指标差是()秒。
A.-20
B.-10
C.+10
D.+20
参考答案:B
阅读课本Unit7《Enjoy your hobby》的这封信,回答下列问题。
1. Who did Brain write to?
____________________
2. Did he want to get back the stamp on the letter?
3. What does their teacher say?
4. What is Jenny's idea?
脑出血的最常见的病因为
A.高血压
B.先天性动脉瘤
C.脑动脉粥样硬化
D.动静脉畸形
E.烟雾病