To learn a foreign language well is useful ,I think.I think__ __to learna foreign language well .

问题描述:

To learn a foreign language well is useful ,I think.I think__ __to learna foreign language well .
求解和为什么是这个解,

it useful
这里使用了主谓宾加it(形式宾语)+useful(宾补)+ 动词不定式(真正宾语)的结构.
很高兴为你解答!
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