But the thought of what it would take to stop what she had set in motion was overwhelming; it would require an amount of tact and gentleness that she felt was impossible to summon.
That option, of blunt refusal, doesn't even consciously occur to her — she assumes that if she wants to say no she has to do so in a conciliatory, gentle, tactful way, in a way that would take "an amount of effort that was impossible to summon".
Rather than just asking the spirits to come and make their presence known, people can try to summon the spirits of specific people and receive information that would be impossible to get in any other way.
When you once believed something that now strikes you as absurd, even unhinged, it can be almost impossible to summon that feeling of credulity again.
I've realized that it's nearly impossible to summon the "right" words while simultaneously processing the news that someone you love has a life-threatening illness.
If Fortis had been British, rather than Belgian, it is impossible to think she would have been summoned by the chancellor for a job at the Bank of England spotting financial risks.
Once she had summoned up these memories, such rich material was impossible to resist.
It is impossible to say if Manning will be able to hold up over the course of a season, if the magic he regularly summoned in Indianapolis will come so easily again, at age 36.
Zombies are impossible to eradicate.
"It's impossible to leave".
