Two big guns are fired, and it is the __________ for the celebrations to begin.
| A．mark | B．sign |
| C．signal | D．symbol |
The moment ______Leo will never forget is ______he joined the Air Force
| A．when; that | B．that; that | C．that; when | D．when; / |
I prefer to work here because salaries are higher here than ______in my country.
| A．that | B．the ones | C．those | D．one |
The girl ___on the ground ___to me that she had ____the book on the shelf.
| A．lying; lay; laid | B．lay; lied; laid |
| C．lying; lied; laid | D．lie; lied; lay |
______himself to his research on the IT technology, he soon made a breakthrough.
| A．Devoted | B．Devoting | C．Devote | D．To devote |
_____the cause of the oil leaks, the specialists can not draw a conclusion before completing a thorough and detailed investigation.
| A．With regard to | B．Regardless of |
| C．In response to | D．In spite of |