One child was mentally retarded.

一个孩子是迟钝的。

He was so slow that many thought him mentally retarded.

他迟钝得很，许多人以为他智力低下。

Hill also has claimed he should not be executed since he is mentally retarded.

希尔声称，他不该被判死刑，因为他智力迟钝。

Those children who have impaired eyesight or hearing or are mentally retarded can also go to special school.

那些视力，听力，智力有缺陷的儿童也可以入学。

Schools, families and communities are three main ecological environments in mentally retarded children's life.

学校、家庭、社区是智力落后儿童生活的三个主要生态环境。