请帮我看看这种英文句型有没有问题,如果有,要怎么改

题目

请帮我看看这种英文句型有没有问题,如果有,要怎么改
-There are 2 essential factors need to beconsidered when choosing a supplier in another country.
-There are 2 essential factors need to be considered when aiming to improve the health of the workforce.
-There are 2 essential factors need to be considered whenpreparing to sell a company.
-There are 2 essential factors need to be paying attention on whenworking in a multi-cultural environment..

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