Object questions are easy, if in the sentence there is just a main verb, showing the whole action. What if there is an infinitive of purpose with an (prepositional) object?
How does one make object questions for the nouns following infinitives at the end of these example sentences?
Highway systems were built to connect the suburbs. He bought some flowers to give to his wife. He locked the door to keep strangers out.
I've been going trough a dozen of American and British grammar books I was able to get my hands on. I've found nothing on this particular problem. They keep it short and simple.
I guess adding a wh-word at the end of that statements is a safe option, isn't it?