hey! please tell me what queries I should ask to any host before choosing him?

This is very important for you to check all the features provided by host whether it may be price or free space.

the technical support is very important because technical support should be readily available. Your average hold time should not greater a couple of minutes.

more questions are: how strong is their technical support division?
What do they provide?
When are they available?
Does tech support cost extra?because it can enhance our expenditure.

Apart of these the server should have different datacenteres so that they can protect our site database for any misfortune and should contain firewall through which they make security more powerful.