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13. He didn't become a teacher of English until 2001,
It was not
14. It takes me 30 minutes to ride to school.
I spend
15. The teacher started to write the lesson plan right after he returned home from the work.
Hardly had
16. He is very poor. He can't buy a second hand bike.
He is so
17. Students must hand in their assignments before the deadline.
It is essential that____________
18. It rained heavily, so he didn't go to school.
Had it not
19. He can draw portrait in 5 minutes.
His portrait can
20. It often takes me thirty minutes to walk to school.
I often spend