Many people already know the risks adults take when they choose to smoke. Dangers from smoking include poor general health, lung problems, cancers, heart disease, and many other problems.
But many people do not know the dangers of smoking for an unborn baby. A pregnant mother and her unborn baby are connected.
A temporary organ called the placenta connects them. The placenta takes important substances like food and oxygen from the mother's blood.
It passes these substances to the baby. It also takes waste substances from the baby back into the mother.
The placenta can take out some harmful substances before they reach the baby. But it cannot take out all of them. 下载全新《每日英语听力》客户端，查看完整内容