齐桓公确立霸主地位的主要方式是[ ]
A．管仲改革
B．尊王攘夷
C．组织会盟
D．问鼎中原
答案：C
The reason why he was late was ___he had taken a wrong bus.
A．because
B．whether
C．because of
D．that
举例说明什么是语言变体。
