西周灭亡的主要原因是[ ]
A．西周实行分封制
B．西周等级森严
C．周厉王的暴政
D．周幽王昏庸无道，矛盾激化
答案：D
The National Day Parade for the 60th anniversary of the founding of China is so grand that it certainly doesn't _____ the whole nation．
A．let down
B．calm down
C．break down
D．set down
