I didn’t know .A. when did the plane take offB. when the plane took offC. when the plane t

I didn’t know .
A. when did the plane take off
B. when the plane took off
C. when the plane takes off
D. when does the plane take off

A. when did the plane take off(答案→)B. when the plane took offC. when the plane takes offD. when does the plane take off解析：特殊疑问词作宾语从句，将特此作为连接词，后接陈述句语序。故选B

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