A.After World WarⅠ, the imperialists stepped up their aggression against China while the Northern Warlord Government resorted to compromise and capitulation externally and to ruthless oppression of the people internally, thus landing China in a grave national crisis.
 B.The imperialists strengthened their aggression against China after World WarⅠand the Northern Warlord Government externally compromised and capitulated and internally oppressed the people which brought about China a grave national crisis.
 C.After World WarⅠ, the imperialists’ aggression against China and Northern Warlord Government’s external compromise and capitulation and internal oppression to the people brought about China a grave national crisis.
 D.After World WarⅠ, the imperialists stepped up their aggression against China while the Northern Warlord Government resorted to external compromise and capitulation and internal ruthless oppression of the people, both of which landed China in a grave national crisis.
参考答案：……