Some researchers believe that there is no doubt ________ a cure for AIDS will be found.
| A．which | B．that | C．what | D．whether |
The companies are working together to create ________ they hope will be the best means of transport in the 21st century.
| A．which | B．that |
| C．what | D．who |
What some people don't realize is ________ difficult life can be after they get addicted to drugs.
| A．that | B．how |
| C．why | D．what |
Don't put off till tomorrow ________ you should do today!
| A．what | B．when |
| C．that | D．which |
—Don't you believe me?
—________， I'll believe ________ you say.
| A．No; whatever | B．Yes; no matter what |
| C．No; no matter what | D．Yes; whatever |
The reform has changed the whole nation. It cannot remain ________ it used to be.
| A．what | B．where |
| C．which | D．when |