Can you please tell me how to choose a particular field of the lookup which have questions? in each lookup there are questions (it's test app). the user selects a particular test and needs questions of the selected test. help :(

Clicking on a button and moving to a new page with questions:
public PageReference runTest () {
        insert newSession; 
        PageReference ref = new PageReference ('/apex/LaunchTests');
        return ref;
    }

Controller:

public class LaunchTestsController {
    public List <Test_item__c> newItem { get; set;} 
    public LaunchTestsController () {
        string str = 'SELECT Id, Question__c, Response__c, Response1__c, Responce2__c, Answer__c FROM Test_item__c';
        this.newItem = Database.query(str);
    }
}

VF Page:

<apex:page controller="LaunchTestsController" >
    <apex:form >
    <apex:pageBlock title="Questions">
        <apex:pageBlockTable value="{!newItem}" var="item">
        <apex:column value="{!item.Question__c}"/>
        </apex:pageBlockTable>
        </apex:pageBlock>
    </apex:form>
</apex:page>