Stephen Hawking believes that the earth is unlikelyto be the only planet __________ life has developedgradually.
He broke __ the Freedom Party and joined the Worker’s Party.
Lincoln’s mother died ___ the farm ___ a cold winter morning of 1818.
Lincoln’s mother did ___ many books ___ him.
He is ___ help now; he is dying.
At the gate of the exhibition hall ,we were requested to ___ our tickets.