I urgently need to know which of the following sentences are possible.
1) Caliban has been reduced to slaveryC by Prospero.
2) He has been enslaved by Prospero.
3) He is subject to Prospero.
4) He is a slave to Prospero.
Prospero has enslaved him.
5) He has made a slave of Caliban.
Ariel informs Prospero of Caliban's plan to kill him.
6) When Prospero is stranded on the island, he managed to release Ariel, which had been kept prisoner in the trunk of a tree by the witch Sykorax.
1) Caliban has been reduced to slavery by Prospero. OK
2) He has been enslaved by Prospero. OK
3) He is subject to Prospero. no
4) He is a slave to Prospero. OK
Prospero has enslaved him. OK
5) He has made a slave of Caliban. OK
Ariel informs Prospero of Caliban's plan to kill him. OK
6) When Prospero is stranded on the island, he managed to release Ariel, which<~~not OK had been kept prisoner in the trunk of a tree by the witch Sykorax.