Third-person singular simple present indicative form of speculate.(verb)
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Use "speculates" in a sentence
"Darwin speculates that the real "knowledge of good and evil" may have been the realization of the cruelty involved in hunting animals for sustenance"
"Starobin speculates that Putin may be shifting Russia away from the religious dead zone it occupied during the Soviet era to what Starobin terms a "Patriotic Orthodoxy" — a strong government animated by a current of religion."
"Safin speculates that he didn't get healthy until after the French Open, which ends in early June."