a. 想像的, 推测的, 推想的

[ adj ]
based primarily on surmise rather than adequate evidence
<adj.all>
theories about the extinction of dinosaurs are still highly conjecturalthe supposed reason for his absence
suppositious reconstructions of dead languages
hypothetical situation

Suppositional \Sup`po*si"tion*al\, a.
Resting on supposition; hypothetical; conjectural; supposed.
--South.