有只蚂蚁在你腿上爬。

There's an ant ___crawling up your leg.

大红蚂蚁在野餐垫上到处爬。

Big red ants were ___crawling all over the picnic blanket.

观察甲虫如何爬过障碍物可以洞察昆虫的运动方式。

Observing how the beetle ___crawls over obstacles provides insight into insect locomotion.