Only when he was refused by the interviewer ____ the importance of knowing English.
| A．was he fully aware of | B．he was fully aware of |
| C．was fully he aware of | D．he fully was aware of |
_____more countries can use natural energy in the future remains to be seen.
| A．Whether | B．This | C．who | D．If |
It worried her a bit _____her hair was turning gray.
| A．while | B．if | C．that | D．for |
.____the meeting should last two days or three days doesn’t matter.
| A．That | B．Whether | C．If | D．Where |
Is _____he said really true?
| A．that | B． what | C．why | D．whether |
The question came up at the meeting_____ we had enough money for our research.
| A．that | B．which | C．whether | D．if |