这句before后面从句时态的用法是怎么回事?you must first establish the primary cause of waste generation before attempting to find solutions.
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这句before后面从句时态的用法是怎么回事?you must first establish the primary cause of waste generation before attempting to find solutions.
这句before后面从句时态的用法是怎么回事?
you must first establish the primary cause of waste generation before attempting to find solutions.
这句before后面从句时态的用法是怎么回事?you must first establish the primary cause of waste generation before attempting to find solutions.
before 后面的是you attempt to find solutions的省略形式.又如:Knock at the door before entering.=Knock at the door before you enter .
before在这里是介词后面不是一个句子,所以不涉及到动词的时态问题。介词后面只能跟名词性的词也包括doing那我又不明白了,attempt本来就是名词,干嘛还加ing啊attempt可以是名词,也可以作动词。在这里,后面有宾语to do,所以attempt是动词。attempt to do 打算做某事,计划做某事。...
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before在这里是介词后面不是一个句子,所以不涉及到动词的时态问题。介词后面只能跟名词性的词也包括doing
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