There are many causes to these problems, and certain preventive measures should be enforced to solve them.

preventive 是由动词 prevent（预防、防止）加上形容词后缀 -ive 构成的形容词，意思是"预防性的、防止的"。preventive measures 指"预防措施"，即为了防止问题发生而采取的行动。