They prepared man­made rubber as a substitute________ the natural rubber that they could no long

题目简介

They prepared man­made rubber as a substitute________ the natural rubber that they could no long

题目详情

They prepared man­made rubber as a substitute________ the natural rubber that they could no longer obtain.
题型:完形填空难度:中档来源:不详

答案

for 
句意:他们用人造橡胶替代无法再获取的天然橡胶。substitute“代替品”后接for,与句意相符。

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