Q: If He concluded that a brief intervention might have a short-lived effect that degrades over time., can we say that "Brief interventions may not have the greatest long term impact."?

A: yes

Q: If Again they met with no success., can we say that "It was simply impossible for anyone."?

A: it is not possible to tell

Q: If How...why? , can we say that "Why did this happen?"?

A: it is not possible to tell

Q: If Her present part was of the adventuress rather than the adventurous order, but she did not deny its possibilities., can we say that "She was more of a stay-at-home type than an adventuress."?

A:
no