Answer:
1. speculative - abstract, conceptual, intellectual
Sentence: These and other scenarios are highly speculative, yet they continually overshadow more urgent and plausible issues.
2. responsible - accountable, amenable, answerable
Sentence: It's hard to tell, though, whether these new revelations will bring all responsible for the violence to justice.
3. delight - pleasure, treat, comfort
Sentence: We have to surprise and delight the consumer audience with the best online shopping experiences.
4. continue - remain, stick around, endure
Sentence: The officials expect this to continue once the ground forces move in.
5. hinder - clog, hold back, obstruct
Sentence: Wider adoption of cloud storage services by organizations has been hindered by security and privacy issues.
