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Are these sentences grammatical? And if not, could you rewrite for me or explain what wrong inside is? Please (I am an English learner, and memorize vocabularies by making sentences but wonder their grammar)
It is proper for him to annihilate the monstrous snake by mundane from his instinct mind, but he complicated the master of the snake.
Since his arithmetic ability is not as bad as we think, I am still dispute why didn’t he beat down with that peddler with intricate trade.
I contempt for things such as that an inferior is beaten off by his superior with stiff force.

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