`III`
`1.` It takes him 30 minutes to swim every morning
`2.` This pupil got used to preparing his lesson carefully before going to school
`3.` The letter was sent to my sister last week
`IV`
`1.` These machines used to be started by hand
`2.` The pencil which is on that desk belongs to me
`3.` George used to be faster than he is now
`4.` I wasn't early enough to see her
