音标：[ 'ru:lə ] 发音:
- Look at a ruler to see how small this is .
- Peter the great was a russian ruler .
- I need fifty sheets of plain paper and a ruler .
- They were welcomed at both places by the rulers .
- The country was bled white by her foreign rulers .
- I find such profound differences among our rulers .
- Prince is on his brow, and ruler in his bearing .
- In 1753, a palace revolution there placed on the throne a ruler .
- Many conquered nations had to pay tribute to the rulers of ancient rome .
- One day some of the rulers of carthage came to the prison to talk with reglus .
A ruler, sometimes called a rule or line gauge, is an instrument used in geometry, technical drawing, printing and engineering/building to measure distances and/or to rule straight lines. Strictly speaking, the ruler is essentially a straightedge used to rule lines, but typically the ruler also contains calibrated lines to measure distances.