one way to make a long sentence easier --------------------is to use the preparetory subject it
问题描述：
one way to make a long sentence easier --------------------is to use the preparetory subject it
A understand B understanding Cto understand Dto be understood
答
因为,这里已经有一个谓语动词是 is 了
因此要用非谓语·此外,sentence 【句子是被理解的】,因此用不定式的被动语态to be done 即答案
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