I think the Grand Canyon is unusual natural wonder of the world.
---Tim played the guiter very well in the school talent show.---I think so.He practices________it every day.
---What about _______ a rest?---OK!Let’s go for a walk.
You should _______ in the dictionary when you meet a new word.
It’s a good idea _____ a pen friend to practise English.
How many ______ medicine are used for the children of six years old?