The X-factor is the unknown form of Bekele.
The Dutchman is in Rio but in unknown form after breaking his wrist in the Tour's late stages.
Most of the mass of the universe is believed to be in "dark matter," a still unknown form of matter.
Health officials must confront two crucial questions: Is SARS an unknown form of a known disease like influenza?
Dr. Primack, his tie providing mute acknowledgment, added that an unknown form of dark energy permeating space is apparently pushing against gravity on large scales.
In their study of the orchid Holcoglossum amesianum, LaiQiang Huang at Tsinghua University, Shenzhen, China, and colleagues discovered a previously unknown form of pollination in a flower.
Slights, grievances, disobliging remarks – he curates the offences of others as carefully as a lepidopterist collects butterflies while also admitting that "making oneself obnoxious to famous persons is not an unknown form of self-introduction".
But under these conditions, with daily re-enactments of the cold war, what Fetisov saw was what he wanted to see, or what he was pressured to see as the Russians push for retribution of some unknown form.
