What is the woman worrying about at first?
A. She wouldn’t dare to eat the snails.
B. They might not be able to afford the food there.
C. The man wouldn’t like the French dishes in the restaurant.
D. They wouldn’t have enough time to have dinner.
查看答案
What does the woman plan to order as the main course?
A. Salmon.
B. French cheese and white wine.
C. Roast duck.
D. Snails and green salad.
设A，B，C是任意集，则下列等式正确的是（）。
A-B=A∩~B
B. (A∪B)-C=(A-C)∩(B-C)
C. (A-B)∪B=A-B
D. (A∪B)∩A=A-B
设A，B，C是任意集，则下列表达不正确的是（）。
A. (A-B)⊆A
B. A⊆A∪B
C. A∪B=B当且仅当A ⊆B
D. A-B⊆A
E. ~（A∪B）=~A∪~B
集合运算的运算律（基本恒等式）与逻辑联结词的运算律（基本等值式）有很大的相似性，可以类比记忆。
A. 对
B. 错
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