Keep yourself warm.
Let's be careful not to catch a cold.
Please be careful not to get heat stroke.
Look out that you don't catch cold.
Let's be careful not to catch a cold.
Look out that you don't catch cold.
Be careful [Take care] not to catch cold.
Look out that you don't catch cold.
Please be careful not to get sick from the summer heat.
Please take care not to get heat stroke.
風邪をひかないように気を付けるべきだ。
You should take care not to catch cold.
Be careful not to take cold.
You must guard against catching cold.
風邪をひかないようにセーターを持って行きなさい。