阅读《出师表》，解释下列划线词语。

1、崩殂                                                                

2、此诚危急存亡之秋也                                        

3、盖追先帝殊遇                                                  

4、以光先帝遗德                                                  

5、恢弘志士之气                                                  

6、陟罚臧否                                                         

7、以昭陛下平明之理                                           

8、是以先帝简拔                                                  

9、以遗陛下                                                         

10、悉以咨之                                                       

11、亲贤臣，远小人                                             

12、痛恨于桓灵也                                                

13、躬耕                                                              

14、卑鄙                                                              

15、由是感激                                                       

16、遂许先帝                                                       

17、二十有一年                                                    

18、夙夜忧叹                                                       

19、恐托付不效                                                    

20、深入不毛                                                        

21、以彰其咎                                                        

22、咨诹善道                                                        

23、临表涕零                                                        

用一根长为2.0m的轻杆连接（杆的质量可不计）分别连接质量为1kg和2kg的小球a和b，两小球绕着轻杆中心O的水平轴无摩擦运动，现让轻杆处于水平位置，然后无初速度释放，取g=10m/s²，当杆第一次到达竖直位置时，下列说法正确的是（　　）

A．在竖直位置时b的速度为2

B．在该运动过程中小球b的机械能守恒

C．在该运动过程中a的机械能增加了16J

D．在该运动过程中b的机械能减少了40J