Question

谁会做这道题

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Answer 1

改成命题P：如果这是一道题，那么你会做。有命题a:这是一道题。 b:你会做所以P = a -> b, 命题a说 P是一道题， 所以能知道 a命题的正确性与P一致。所以 假设 当P命题为假时，a为真且b为假，与之前所得相反。所以假设不成立当P为真命题时，a 也是真 且b也是真，符合逻辑，所以P命题为真

Answer 2

1.
He isn't cleaning the room.
Is he cleaning the room?
What is he doing?
2.She isn't washing the dishes now.
Is she washing the dishes now?
What is she doing?