WorksheetPage wbk = m_originApp.WorksheetPages["Book1"];
Worksheet wks = m_originApp.FindWorksheet("[Book1]Sheet1!");
Column col = wks.Columns["B"];

m_originApp.Execute("ltVar = getSum(3, 4);");
string str = m_originApp.get_LTVar("ltVar").ToString();

string strCMD1 = "StringArray sa = getTimeArray(); size = sa.GetSize();";  // LT command to return the stringarray to a LT stringarray variable, and get this array size
m_originApp.Execute(strCMD1);  // execute the LT command
int size = Int32.Parse(m_originApp.get_LTVar("size").ToString());  // get size to C#
// put the string to C# string array
string[] strarr = new string[size];
for(int i = 1; i <= size; i++)
{
    string strCMD2 = "string str$ = sa.GetAt(" + i.ToString() + ")$;";  // LT command to get the ith string
    m_originApp.Execute(strCMD2);
    strarr[i-1] = app.get_LTStr("str$");  // here use the get_LTStr() method
}

m_originApp.Execute("StringArray sa;");  // define a LabTalk string array
for(int i=0; i<size; i++)
{
    string str = "sa.Add(" + strarr[i] + ");";  // add string to array command
    m_originApp.Execute(str);  // add one string to string array
}