(物体内的窟窿) cavity; void
pulmonary cavity
肺空洞
Cavities in teeth are caused by decay.
牙齿上的空洞是由龋蚀造成的。
(无内容) empty; hollow; devoid of content; vague and general
mere phrases; empty phraseology
空洞的词句
an article empty of matter
内容空洞的文章
make an inane remark
作空洞的评论
vague and general proposal
空洞的议论
(洞中发生的声音或回音的; 敲打空容器的声音) hollow
a hollow voice
空洞的声音