Block 表示街区，街道，a new kid on the block字面意思是街区新来的孩子，后来引申为初来乍到的人，新鲜玩意，新生事物

【例句】
As I amthe new kid on the blockI know that I will have to work hard to prove myself.
因为我是新人，我知道我必须努力工作来证明我自己。

She isn'tthe new kid on the blockanymore. She has been working here for a year already.
她再也不是菜鸟了。她已经在这边任职一年了。