加之

jīng jì fā zhǎn tíng zhì bù qián jiā zhī qīng shào nián rén shù jī zēng kě néng shì měi guó fàn zuì lǜ shàng shēng de bù fen yuán yīn

经济发展停滞不前，加之青少年人数激增，可能是美国犯罪率上升的部分原因。

A stagnant economy combined with a surge in the number of teenagers is likely to have contributed to rising crime levels in the U.S.