9.Do you think it worthwhile to spend so much time and money cloning a cow?只是什么句式,为什么不是it is

9.Do you think it worthwhile to spend so much time and money cloning a cow?只是什么句式,为什么不是it is
9.Do you think it worthwhile to spend so much time and money cloning a cow?
只是什么句式,为什么不是it is

9.Do you think it worthwhile to spend so much time and money cloning a cow?只是什么句式,为什么不是it is
这是复合句,it是形式宾语,真正的宾语是动词不定式,

这是一个固定用法
it adj to do sth
例：
1 It is important to drink enough water every day.
it形式主语，没有意思的，to drink enough water every day真正主语，意思是：每天喝足够的水很重要。你看，主语那么长，而谓语就is important 那么短，是不是头重...

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这是一个固定用法
it adj to do sth
例：
1 It is important to drink enough water every day.
it形式主语，没有意思的，to drink enough water every day真正主语，意思是：每天喝足够的水很重要。你看，主语那么长，而谓语就is important 那么短，是不是头重脚轻啊，为了句子平衡，使用了形式主语，而把真正主语放在后面，所以句型：it‘s+adj+to do 的意思是：做某事怎么样。
2 Doctors think it is important to drink enough water every day.
这时候It is important to drink enough water every day.
是宾语从句，作think的宾语。因为think 可以形成think+ 宾语+宾语补足语，所以此句可改成Doctors think it important to drink enough water every day.
也就是少了be动词is.此时，it是形式宾语
important为宾语补足语to drink enough water every day为真正宾语。
能这样用的，除了find外，常见的还有：find,believe等

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it 是形式主语，真正的主语是to 后面的一句。