While building a tunnel through the mountain, ________ .
| A．an underground lake was discovered |
| B．there was an underground lake discovered |
| C．a lake was discovered underground |
| D．the workers discovered an underground lake |
Sales of CDs have greatly increased since the early 1990s, when people_____to enjoy the advantages of this new technology.
| A．begin | B．began | C．have begun | D．had begun |
________ is often the case, we have worked out the production plan.
| A．Which | B．When | C．What | D．As |
The____________house smells as if it hasn't been lived in for years.
| A．little white wooden | B．little wooden white |
| C．white wooden little | D．wooden white little |
The old man, ____________abroad for twenty years, is on the way back to his motherland.
| A．to work | B．working | C．to have worked | D．having worked |
A man is being questioned in relation to the ________ murder last night.
| A．advised | B．attended | C．attempted | D．admitted |