Closed under union
[计] 对\或\运算封闭
🧩 词语组成解析
closed
[klozd]
adj. 关闭着的，封闭着的;密闭着的，保密的;<美>准备好了的，定了契约的;
v. “close”的过去式和过去分词;
clos=close关闭+ed已...的→关闭了的
under
['ʌndɚ]
prep. 在…下面，在表面之下;在…的假定表面或掩饰下;少于，小于;在…情况下;
adv. 在下面;少于;在水下;在昏迷中;
adj. 较低的，下面的;
🗣️ 情景例句
This is a tough job.
这是一件困难的工作。
I have come to make sure that your stay in Beijing is a pleasant one.
我特地为你们安排使你们在北京的逗留愉快。
If there had not been a hard layer of rock beneath the soil, they would have completed the job in a few hours.
如果不是因为土壤下面有一层坚硬的岩石，他们的营救工作仅用几个小时就可以完成了。