The police failed to come up with ______ evidence, and on that account the suspect was released.
| A．effective | B．valid | C．subtle | D．considerate |
She took it for granted _________ I'd be back home an hour later.
| A．that | B．whether |
| C．if | D．When |
_________ caused the accident is still a complete mystery.
| A．What | B．That |
| C．How | D．Where |
It is widely _________ that smoking can cause cancer.
| A．believed | B．think |
| C．say | D．Hoped |
_________ appeared to me that he enjoyed the food very much.
| A．What | B．It |
| C．All that | D．That |
_________ all the inventions have in common is _________ they have succeeded.
| A．What; what | B．That; that |
| C．What ； that | D．That ； what |