The number of crimes has decreased because the punishment has been made more severe.
この文章が以下のように翻訳されています。
厳罰化されたので、犯罪数は減った。 ー The number of crimes has decreased because the punishment has been made more severe.
厳罰化された ー the punishment has been made more severe / it is more severely punished
ので、 ー because
犯罪数は ー the number of crimes / the amount of crimes
減った。 ー has decrease / has dropped
参考になれば嬉しいです。