28. Word came, as expected, ______ college entrance English exam will be reformed soon.
| A．it | B．what | C．which | D．that |
It is by no means clear the president can do to end the strike.
| A．how | B．which |
| C．that | D．what |
（年北京市西城区高三5月二模试题）31. A person who has never tasted bitter won’t know ______ sweet is.
| A．which | B．what | C．when | D．why |
It suddenly occurred to him he had left his keys in the office.
| A．whether | B．where | C．which | D．that |
（年北京市西城区高三5月二模试题）23. It’s been discovered in the study ______ people are more relieved after forgiving others.
| A．that | B．what | C．which | D．whose |