Delphi的关键字问题

为什么我用Delphi做了个界面，然后进行模糊查找，写有如下代码：
procedure Tfrm.BitBtn1Click(Sender: TObject);
var
  tj,tj1,tj2,tj3,tj4,tj5,tj6,tj7:string;
begin
  tj1:='1=1';
  if checkbox1.Checked then
  tj1:='GH like'"+'%'+Edit1.Text+'%'+"'';

  tj2:='1=1';
  if checkbox2.Checked then
  tj2:='XM like'"+'%'+Edit2.Text+'%'+"'';

  tj3:='1=1';
  if CheckBox3.Checked then
  begin
  if RadioGroup1.ItemIndex=0 then
  tj3:='XB like '"+'%男%'+"'';
  if RadioGroup1.ItemIndex=1 then
  tj3:='XB like'"+'%女%'+"'';
  end;

  tj4:='1=1';
  if CheckBox4.Checked then
  tj4:='CSRQ>=#'+DateToStr(DateTimePicker1.Date)+'# and CSRQ<=#'+DateToStr(DateTimePicker2.Date)+'#';

  tj5:='1=1';
  if CheckBox5.Checked then
  if CheckBox8.Checked then
  tj5:='HF=true'
  else
  tj5:='HF=false';

  tj6:='1=1';
  if CheckBox6.Checked then
  tj6:='ZC like '"+combobox1.text+"'';

  tj7:='1=1';
  if CheckBox7.Checked then
  tj7:='GZ>='+Edit3.Text+' and GZ<='+Edit4.Text;

  tj:='select * from zg.db where'+
  t