__________ to sun, rain and wind for a long time, the stone split（裂开）.
| A．Being exposed | B．Having exposed | C．Exposed | D．To expose |
The traditional view is ______ we sleep because our brain is “programmed” to make us do so.
| A．when | B．why | C．whether | D．that |
______ he referred to in his article was unknown to the general reader.
| A．That | B．What | C．Whether | D．Where |
____ matters most in learning English is enough practice.
| A．What | B．Why | C．Where | D．Which |
Engines are to machines _________ hearts are to animals.
| A．as | B．that | C．what | D．which |
____ team wins on Saturday will go through to the national championships.
A. No matter what B. No matter whichC Whatever D. whichever