Kēhuàn xiǎoshuō chōngmǎn le duì wèilái de huànxiǎng.
Science fiction is full of fantasies about the future.
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usage
幻想 can be neutral (childhood fantasies) or slightly negative (unrealistic illusions). 科幻 = science fiction (abbreviation of 科学幻想). Compare: 梦想 (dream/aspiration, more positive), 妄想 (delusion, more negative).
