日期:
来源:雅诚德英语网
By the 16th century, a pendulum clock had been devised, but the pendulum swung in a large arc and thus was not very efficient.
到了16世纪,人们发明了摆钟,但钟摆摆动的幅度很大,因此效率不高。
By the 16th century, a pendulum clock had been devised, but the pendulum swung in a large arc and thus was not very efficient.
到了16世纪,人们发明了摆钟,但钟摆摆动的幅度很大,因此效率不高。