问题描述：
At last ,Mary _____ hard work and became an ORBIS nurse
At last ,Mary _____ hard work and became an ORBIS nurse.
A.got used to do B.used to do C.got used to doing D.used to doing
At last ,Mary _____ hard work and became an ORBIS nurse.
A.got used to do B.used to do C.got used to doing D.used to doing
问题解答：
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