Hi,

Need help on the below trigger for the lines marked in red. I am able to cover 52% of code, but I am facing difficulty for the below lines marked in red. 

trigger SurveyGuest on SurveyTaker__c (before insert,before update)
{
for(SurveyTaker__c st:trigger.new)
{

st.Guest_Profile__c=st.hg__c;
try
{ Visit_Details__c vs =[Select Overal_Points__c,Guest_Name__c from Visit_Details__c where id=:st.Transaction_Detail__c];

Survey__c sr =[Select id ,Maximum_Points__c,Points_Required_Minimum__c,Email_Template_Id__c,Email_Address__c, Points_for_Loyalty_programme__c from Survey__c where id=:st.Survey__c];
if(vs.Overal_Points__c==null)
vs.Overal_Points__c=0;
vs.Overal_Points__c = vs.Overal_Points__c+ sr.Points_for_Loyalty_programme__c ;
st.Guest_Profile__c=vs.Guest_Name__c;
if(((st.Points_Earned__c/sr.Maximum_Points__c)*100)<sr.Points_Required_Minimum__c)
{
EmailTemplate e = [select Id,Name,Subject,body ,htmlvalue from EmailTemplate where Id=:sr.Email_Template_Id__c];
List <String> toAddresses =new List <String>();
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
toAddresses.add(sr.Email_Address__c);
mail.setToAddresses(toAddresses);
if((e.htmlvalue!=null)&&(e.htmlvalue!=''))
mail.setHtmlBody(e.htmlvalue);
else
if((e.body !=null)&&(e.body !=''))
mail.setHtmlBody(e.body );
mail.setSubject(e.Subject);
Messaging.sendEmail(new Messaging.SingleEmailMessage[] {mail});
}
update vs;

}
catch(exception e)
{
}
}

}

Kindly help ASAP.