lǎo shī / ràng / wǒ men / xiān / liáng chū / zhè kuài / jǔ xíng / cài dì / de / cháng / hé / kuān / zài / jì suàn / tā / de / zhōu cháng

老师让我们先量出这块矩形菜地的长和宽，再计算它的周长。

The teacher asked us to measure the length and width of this rectangular vegetable plot first, and then calculate its perimeter.