____you have done might do harm____other people.

A.That;to　　　　B.What;to　　　　C.What;for　　D.That;for

_______ you have done might do harm to other people.  

　　A. That       B. What        C. Whether    D. How

_ you have done might do harm to other people.
 A. That  　　　　 B. What   　　　　C. Which  　　　　　 D. This

________ you have done might do harm to other people.

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________ you have done might do harm to other people.

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