13. She was the person who I was talking with yesterday
= She was the person about whom I was talking yesterday .
14. She was at the garden party whom I was telling you about.
= She was at the garden party about whom I was telling you.
15. Near where I live there's a wood where you can find woodpeckers.
= Near where I live there's a wood where you can find woodpeckers.
16. The fancy-dress party, which the men all turned up as gangsters, was held in Manhattan.
= The fancy-dress party, at which the men all turned up as gangsters, was held in Manhattan.
Lưu ý:Chỉ có whom, which có giới từ đi kèm
$#FromTha$