must有过去式吗?can,may都有过去式,must怎么办.比如：she was a hard-working student,because she believed that she ____ work hard.她相信她必须好好学习.这个"必须"怎么填...

分类: 作业答案 • 2022-02-18 16:37:30

问题描述：

must有过去式吗?can,may都有过去式,must怎么办.比如：she was a hard-working student,
because she believed that she ____ work hard.她相信她必须好好学习.这个"必须"怎么填...

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