到上学期末为止,苏珊已经学了1000个英语单词.(by)
问题描述：
到上学期末为止,苏珊已经学了1000个英语单词.(by)
答
By the end of this team,Susan has learned 1000 English words.
By是现在完成时的标志,用现在完成时（have/has+done）.
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