19. They have never heard such a thing before. This is the first time ________________________________________________ 20. I haven't been to HCM city for 2 years. The last time _________________________________________________________ 21. She hasn't written to us since last year. The last time _________________________________________________________ 22. She hasn’t had a swim for five years. She last ______________________________________________________________ 23. This is the fìrst time I saw this fìlm. I have never __________________________________________________________ 24. This is the first time he went abroad. He hasn’t ____________________________________________________________