23. No doctor will prescribe any new drug if he is confident enough that it will work.
A B C D
A. 1. Any doctor is prescribing
2. A doctor prescribed
3. The doctor has prescribed
4. A doctor will not prescribe
B. 1. for some new drugs 2. with new drugs
3. the drugs that are new 4. of the drugs which are new
C. 1. if he is with enough confidence
2. unless he is confident enough
3. should he have enough confidence
4. if he will feel confident enough
D. 1. which will work 2. in order that it can work
3. that is working well 4. so that it might work well