点击下方单词,选择对的这个单词
点击下面链接下载与本句相关的学习资源，包括PDF教材和音频练习，方便课后复习：
及物动词
不及物动词
名词
1. a passageway through or under something, usually underground (especially one for trains or cars)
e.g. the tunnel reduced congestion at that intersection
2. a hole made by an animal, usually for shelter
Synonym: burrow
多通过句子记忆单词，而不是单独死记硬背。
