Which are not compound propositions in the following propositions？ Multiple choices（）
A. I can’t sing
B. If it doesn’t rain,I’ll go out
C. I have classes every day
D. Are there people on Mars
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”Stinky tofu stinks and smells good” is a false statement.Which law does this use（）
A. Law of identity
B. Law of excluded middle
C. Law of contradiction
D. Absorption law
Which is a proposition in the following statements（）
A. Please don’t copy!
B. The sun is a planet
Can I smoke here
D. x – y = 3
What is the type of（）
A. tautologies
B. contradiction
C. Nontautological satisfiable formula
D. Unable to determine
German Nazi leader goebbels once said that a lie repeated three times becomes a truth.Which law does this violate（）
A. Law of double negation
B. Idempotent law
C. Associative law
DE Morgan law
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