英语每日一句
The first calendar *to fix these days on definite dates of the year *was the solar calendar，*which had 365 days in a year and —every four years— a “leap-year” with one extra day.
solar calendar 日历
leap year 闰年
fix...... on.. 固定
to引导的动词不定修饰the first calendar
which 非限定从
