it caused在这里做插入语,原句是the earthquake and tsunami (it caused) did great damage to Japan and affected the global economy,即（它造成的）地震和海啸对日本造成了很大灾难并影响了全球经济,it在这里指前面的the earthquake and tsunami.
插入语中的谓语与插入语中的主语保持一致,外面的句子就不受插入语的时态影响了.
希望有所帮助.
the earthquake and tsunami_(C)___caused did great damage to Japan and affected the global economy
A.which B.this C.it D.what 谁能解释一下为什么选c还有像这样的句子谓语动词是与it前边的主语保持一致还是与it保持一致?
it caused在这里做插入语,原句是the earthquake and tsunami (it caused) did great damage to Japan and affected the global economy,即（它造成的）地震和海啸对日本造成了很大灾难并影响了全球经济,it在这里指前面的the earthquake and tsunami.
插入语中的谓语与插入语中的主语保持一致,外面的句子就不受插入语的时态影响了.
希望有所帮助.