sked to explain _____ he did to make hisstudents so fascinated with his lessons, the teacher paused and thought deeply

______ time ______, what the scientist said finally proved to be true

The book is a bit difficult． read something easier –All right．

Have you _____ had dumplings — No, not _____.

The store sells sweaters ______ a very good price. We can buy one ______ 40 yuan.