请教一道题目

big7474

On the Great Plains, nineteenth-century settlers uesd mud and grass to build their homes, doing it without timbers and nails.
A. settlers used mud and grass to build their homes, doing it without
B. settlers used mud and grass to build their homes, did it without
C. settlers used mud and grass to build their homes, making them while not having
D. settlers used mud and grass to build their homes, making do without
E. settler's homes were built of mud and grass ,making do without

答案是D，小生我就是想不明白make为什么会出现，做何解释。。。