What's usage of 'to' following 'which' in a relative clause?

Question

I see a sentence in a commercial article > Then in 2006, Amazon launched its Elastic Compute cloud (EC2) as a > commercial web service that allows small companies and individuals to > rent computers on which **to** run their own computer applications. I could not figure out the usage of 'to' in the relative clause. Is it wrong or some grammatical rule?

Answer 1

The use of "to" in the example sentence you asked about is part of the infinitive phrase "to run." "To" is not part of the conjunction "which" here that introduces the clause "to run their own computer applications." In other languages like Spanish and French, the infinitive form of the verb is indicated with a specific ending. In English the infinitive form of the verb is indicated with the word "to" in front of the base form of the verb.