It was about 600 years ago ______the first clock with a face and an hour hand was made .
In English colleges, classes are often arranged in freer and opener______and many jobs are designed for students.
— What great trouble I have solving this problem now! —_____ my advice, you ________less trouble.
As is well known to us all, in China pigeons stand for peace. However, in India the wheel in its national flag is also a _______of peace.
It doesn’t make a(an)_______to me whether you go or stay.
How did it______ that humans speak so many different languages?