- This comes after a series of safety lapses that delayed flights and grouded planes.
之前这四家公司因为一系列安全问题而导致航班延误，航线搁浅。
- Radioactive and other hazardous materials present health and safety problems in increasing numbers of countries.
放射性及其它有害物质将给越来越多的国家带来健康和安全问题。
