四级When the rats detect the smell, they stop and rub their legs to indicate a sample is infected.
当老鼠检测到气味时，它们会停下来摩擦腿，以表明样本已被感染。
2017年12月四级真题（第一套）阅读 Section A
四级When two plates push against each other, or when two plates rub against each other, an earthquake will occur.
当两个板块相互推挤时，或者当两块板块相互摩擦时，就会发生地震。
1989年1月英语四级真题
四级The player proceeded to rub his gloves across his wet T-shirt and then exclaimed.
球员开始把手套擦在湿T恤上，然后大声喊道。
2005年6月大学英语四级(CET-4)真题
未经许可，严禁转发。QQ交流群：688169419