Space is, for the most part, emptiness.
太空绝大部分是空洞的。
complacently or inanely foolish.
自满的、空洞的或愚蠢的。
An empty promise is insincere.
空洞的诺言是无诚意的。
an article completely empty of matter
内容十分空洞的文章
They are windy phrases.
它们是空洞的短语。
Empty words or ideas.
废话，空谈空洞的词语或思想
The formation of cavities in a body tissue or an organ, especially those formed in the lung as a result of tuberculosis.
成洞身体组织或器官内空洞的形成，尤指那种因肺结核而在肺中形成的空洞
An animal's hollowed-out habitation, such as a burrow.
洞穴动物中空的洞穴，如地洞
It turned out to be a shallow document.
它结果竟是一份空空洞洞的文件。
A cave or hollow used as a refuge or hiding place.
洞穴一个用于避难或藏身的洞穴或空洞
Speech or writing deemed banal or foolish.
空洞无聊的话或文章
His speech rang hollow.
他的发言听上去很空洞。
as if echoing in a hollow space.
好像空洞里的回声一样。
His preachings rang hollow.
他的说教听起来很空洞。
Empty or pretentious bragging.
吹牛空洞或造作的大话
The condition or quality of being inane.
空虚，空洞空的情况或状态
Why must they write such long and empty articles?
为什么一定要写得那么长，又那么空空洞洞的呢？
A pit dug into the ground or on a hillside and used as a shelter.
防空洞挖在地下或山坡，用作掩蔽体的洞