28. The factory ___I am going to is the place ___my mother used to work many years ago.

A. where, where B. where, which C. which, where D. that, which

27. The place ___ you are going to visit is the ruin of a place.

A. in which B. at which C. where D. which

26. This is one of the means ____ the electric energy is conducted from one place to another.

A. by which B. by that C. through which D. through that

25. In the dark street, there wasn't a single person ____ she could turn for help.

A. that B. who C. from whom D. to whom

24. He paid the boy 10 dollars for washing ten windows, most of ___had not been cleaned for years.

A. these B. those C. that D. which

23. All ___ is needed is a supply of oil.A. the thing B. that C. what D. which

22. The buses, ____were already full, were surrounded by an angry crowd.

A. most of them B. most of which C. which most D. that most

21. ___is natural, he married Mary.A. It B. What C. Which D. As

20. His father died last year, ____made it impossible for him to go abroad.A. when B. which C. as D. that

19. He must be from Africa, ____can be seen from his skin.A. that B. as C. it D. what