Question

fill in preposition
he was killed _____ the robber ____ a knife

Answer 1

he was killed by a robber with a knife
---- ------
HOPE THIS HELPS YOU.....

Answer 2

Answer:  

The appropriate preposition would be: He was killed by the robber with a knife.  

Explanation:

Only these two prepositions would be appropriate here to make it a complete and meaningful sentence. In English use of preposition is very common and important. Prepositions are generally a word that combines with nouns which helps us to write or speak a correct English sentence. It is really important to use the correct preposition for a correct English sentence.