they only started singing earlier this year这里为什么要用比较级earlier?

问题描述:

they only started singing earlier this year这里为什么要用比较级earlier?
又没有其他的事物比较,为什么用比较级啊?
我们听力的上下文给你们发上来,句子意思不是这样的。
Alex: Hey DaveI'm listening to a band called “The Toms”. Have you heard of them yet?
Dave: No, I haven't. Are they a new band?
Alex: Yes, they only started singing earlier this year. But they've already made two CDs.
Dave: Wow, they must be really popular.
根据意思来看,这是一个新乐队,不存在和去年的比较。

其实这里是比较了 只是省略了而已 是跟往年比较的
翻译:他们只是今年开始唱歌(比去年或者比往年)早了些而已看一下问题补充很简单,是跟现在比较,意思是 今年早些时候你能写出此句的完整句子吗?they only started singing earlier than today this year