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。
The number of crimes decreased because the penalties were made stricter.
The number of crimes decreased because the penalties were made stricter.
Stricter penalties led to a decrease in crime.
「厳罰化された(罰則が厳しくなった)」は英語で penalties were made stricter や stricter penalties(より厳しい罰則)、harsher punishments などと表現します。
また、「犯罪数が減った」は the number of crimes decreased や crime dropped と表すのが自然です。