It was about 600 years ago _______ the first clock with a face and an hour hand was made.
-Mr Zhang, you ______ a good rest after the hard work. -Thank you!
There goes the bell and the children are walking out of the classroom ______.
-Who will be ______our class when Mr Liugoes to Beijing for further education? -Mrs Zhao.
Teachers will never be ____ by computers in the classroom though the Internet is popular.
Mr Zhang does well in singing and he is good at gymnastics _____.