end up，pick up，take off，on average，be buried in，catch fire，put out，take place，set fire to，in all

15.He his studies when I came in. 16.The woman poured some water on the box which suddenly. 17.Great changes in our village in the past ten years. 18.The robber his house before he escaped. 19.Before the firefighters arrived，the fire . 20.There are 30 people in the party who will travel to Hainan.

was buried in

caught fire

have taken place

had set fire to

had been put out

in all