______ the average age of the population increases, there are more and more old people to care for.
A:Unless
B:Until
C:As
D:While
Everyone should keep discipline and you are no____ (例外).
2014年
2015年
2016年
养宠物狗比率
12%
8.2%
7.5%
养宠物猫比率
3.1%
4.3%
5.4%
— I am sorry that I've let you down.
一 It doesn't matter. I believe you can do better next time.
若数a的近似数为1.6,则下列结论正确的是( )