1. Those who are toiled to death, those who are worried to death, and those who are bored to death.
    劳累至死的人、忧虑至死的人、无聊至死的人。

2. I´m worried about the safety of the children,
    我为孩子们的安全担心.

3. I am worried about his health.
    我为他的健康担心.

4. I suddenly felt very worried, but could not say anything.
    我突然非常着急起来，但却什么也说不出来。