What is the term for the situation where a company's expenses result in a decrease in its net income compared to the previous year?

在栈中，以下哪个操作会导致栈顶元素被移除？

在量子计算中，Shor算法主要用于解决哪类问题？

Which tense should properly complete this sentence? 'The company ______ its data protection protocols since the cybersecurity incident last year.'

若Cov(X,Y)=5，D(X)=4，D(Y)=9，则Cov(2X+1,3Y-2)等于：