问题详情：
动词填空。
1. Many of the world's inventions have__________ __(creat) simply by surprise.
2. Ben _____________(promise) to keep the secret, so he wouldn't tell anyone even though asked to.
3. He ___________(discover) a pot in the e were 32,000 Chinese metal coins.
4. Ann (practise) colour therapy since she left college.
【回答】
1, been created 2. promised
3. discovered 4. has practised
知识点：语法填空
题型：完成句子
