设关系 R与关系 S具有相同的属性个数，且对应属性的值取自同一个域，则 R -S可记作 ______。
A、{t|t∈R∨t∈S}B
暂无解析
Thewoundedsoldierswouldrecoverquicklyiftheywerewell________.
Peopleappreciate_______withhimbecauseheisknowledgeableandhumorous.
Ourpaymentterms(付款方式)are___,irrevocableletterofcreditforthefullinvoicevalue.()
Thedelegation________RussiawillvisitLondonthisafternoon.
She________everythingelseandconcentratedonthetaskbeforeher.
