1、有be的,在be动词后加 not 如：Here is a car. 否定式 Here is not a car. 2、be 动词原形,在这种情况下,必有助动词或情态动词,在助动词或情态动词后加not. 如：Now he should be in Beijing. 否定式 Now he should not be in Beijing. 3、无be动词,必有一般动词构成句子,在动词前加 do not. 如：The car hit the door. 否定式 The car do not hit the door. 这里加的do not 要和动词的时态相一致.
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