Dear keoSomala
Thank you so much for your replys. Eventhough it is short, it is meaningful and detial enough to understand. So, I would say you are right; the best answer is (a).
:(Anyway, just stating which one is the correct one can not clarify my doubts. Would you please preceed helping me? OK, down here are several other questions related to the topic:
- What does it mean FUTURE FACT? Is it something that 100% happen in the coming consequence?
Now let think about the word"drugs" in the example above
If we assume that the sentence express future fact then the word drugs does carry nucleus meaning of effectiveness and perhaps with efficiency. Do you mean this way?
On the other hand, if you think on the speaker part or speaker side, don't you think it is the speaker's conjecture, based on exerience, on the effectiveness of the drugs? or what?
ALL the problems above really concern me. I hope you would take these things into your consideration so that my doubts will be clarified either.
Thanks in advance

The more you help us, The higher you raise up yourself!
MINO
waiting for your help
