The school has developed an online system________ students can choose their own teachers.
The Japanese suffering from the worst natural disasters .
The experiment shows that proper amounts of exercise, if regularly, can improve our health.
The incident turned him into different person, even if he did not realize it at beginning.
For holidays, many people visit the Great Barrier Reef _______ the northeast coast of Australia, _______ has more than 600 islands.
After 1953 _______ people have succeeded in climbing the mountain.