一年 + 中
The phrase 一年 (yī nián) means 'a year' or 'one year' and is used in time expressions to refer to the span of a single year. It commonly appears in constructions like 一年中 (within a year/throughout the year) to set a temporal scope for comparison or description.
一年中最热的时候就是七八月。
yì nián zhōng zuì rè de shíhou jiùshì qī bā yuè.
The hottest time of the year is July and August.
他用了一年的时间准备这次考试。
tā yòng le yì nián de shíjiān zhǔnbèi zhè cì kǎoshì.
He spent a year preparing for this exam.
一年过得真快,转眼就到年底了。
yì nián guò de zhēn kuài, zhuǎnyǎn jiù dào niándǐ le.
A year goes by so fast; in the blink of an eye it's already the end of the year.