The traffic here is very dangerous for children.

　　這里的.交通對孩子很危險。

　　You're on dangerous ground if you criticize his family.

　　你要是批評他的家人可就惹麻煩了。

　　In those days, the trip across country was a dangerous undertaking.

　　那個時期，越野旅行是一件危險的事情。