When ______ comes to research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.
| A．that | B．it | C．this | D．what |
After driving for five hours, they arrived atthey thought was the place they had been dreaming of.
| A．what | B．that | C．which | D．where |
If you had worked hard, you ______ so anxious now．
| A．are not | B．would not have been | C．will not be | D．would not be |
_____ I’m willing to help, I do not have much time available．
| A．While | B．When | C．Once | D．Since |
The rise of oil prices made scientists search for new energy resources ______ oil．
| A．replace | B．replacing | C．to replace | D．replaced |
You didn’t believe John won the first prize at the speech competition, ______?
| A．did he | B．didn’t he | C．did you | D．didn’t you |