解释下列句中划线的字。

见贤思齐焉                                          ____

不成人之恶                                          ____

不图为乐之至于斯也                                  ____

不以其道得之，不去也                                ____

若以$\left(\begin{array}{c}\begin{array}{ccc}1& a& 3\end{array}\\ \begin{array}{ccc}a& 4& 1\end{array}\end{array}\right)$为增广矩阵的线性方程组有唯一一组解，则实数a的取值范围为____ ．

洞庭湖是我国著名的天然湿地之一，湿地被称为“地球之肾”主要是因为（    ）

    Baron Pierre de Coubertin was a Frenchman. At his time sports were not taught in French schools. De Coubertin believed that sports should go hand in hand with studies. He had an idea. His idea was to begin the Olympics all over again.

    Sports teachers of other countries liked De Coubertin ideas. So in 1896, the modern Olympic Games were held in Athens, Greece. Since then the Olympics have been held once every four years, except three times, when there were wars.

    The modern Olympic games have many foot races and field sports programs. The longest race in the games is called marathon（马拉松）.

    Before the start of the Olympic Games, runners carry lighted torch(火炬) through many nations towards the stadium（体育场 ）where the games will be held. These sportsmen are from different countries. Yet they work together to carry the Olympic torch. It is passed from runner to runner,  When the last runner enters the stadium, he or she places the torch in a special basin filled with oil. It catches fire. It is then, only then, that the Olympic Games can begin.

    The Olympic flame（火焰）burns throughout the games. It is the flame of peace.