题目: Please choose the correct definition for the word PACKED:
A.Describesahouse/roomthatislargeandhasplentyofspace.
B.Describesaroomorhomethatalreadyhasfurnitureandappliancesinit.……继续阅读 »
题目: ① (∀x)(A(x)⋀B(x))⟹(∀x)A(x)⋀(∀x)B(x) ② (∀x)(A(x)⋁B(x))⟹(∀x)A(x)⋁(∀x)B(x)③ (∃x)(A(x)⋁B(x))⟹(∃x)A(x)⋁(∃x)B(x) ④ (∃x)A(x)⋀(∃x)B(x)⟹(∃x)(A(x)⋀B(x))
①(∀x)(A(x)⋀B(x))⟹(∀x)A(x)⋀(∀x……继续阅读 »