영어 문장 구문 해석 부탁드려요

시험 준비 중인데 아래 문장들 해석을 부탁드려요.
선생님이 뜻과 문장을 외우라고만 하셔서 이해가 잘 안 되네요 ㅠㅠ

she ordered the room to be cleaned by eight.
they seemed to have worked together in the past.
I am sorry not to have come on Tuesday.
A rapid increase in the number of college graduates has made the competition for jobs much greater than it used to be.
As youth, we need not feel ashamed of making mistakes in trying to find or win our placce in a social group.
Most of this island, which is more than three times as large a Texas, is continually covered with ice and snow.
Korea imported about three times more from China than from Germany.
Some people paid more than ten timed th regular price for tickets.
David asked if I could help him with his report.
I heard that th had been a detective.
He told me that the building is still under sonstruction.
She said that honesty is the best policy.
Our teacher said that Columbus discovered America in 1492.