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“The use of a poor quality oil can lead to rapid deterioration of its properties with the resultant formation of deposits in the piston crown which in turn results in a considerable reduction in heat transfer with subsequent overheating and thermal cracking” According to this sentence, we can know that the principle reason of the overheating and thermal cracking is（）
A:the use of a poor quality oil
B:the deterioration of its properties
C:the formation of deposits
D:the reduction in heat transfer ability

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出自：海船船员证

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