Premise:
"The shadow shifted again and a gleam of silver slashed in the darkness."
Hypothesis: A silver sword was thrown in the dark.

it is not possible to tell

Premise:
"Seven riders of the warband circled and set another house ablaze."
Hypothesis: The riders torched a house.

yes

Premise:
"Senate race in New York, but not before he had had a conversation with Johnson in which he admitted his own insecurities about making the race."
Hypothesis: Johnson admitted he didn't think he could win.
it is not possible to tell