题目

The summer vacation is coming. During the vacation, you can do what you like and prepare yourself well for the future. You'll enjoy your summer vacation with the help of the following suggestions. ▲Take exercise. After studying hard for months, you must be bored and tired. Taking exercise is the best way to get energy again. Swimming and walking are perfect choices for you. All kinds of exercise are good for your health. ▲Master some basic life skills. You will live an independent life one day. Therefore, you should learn some necessary and useful basic life skills such as washing clothes 下列哪项属于简单的反射活动（　　）A．知无不言B．老马识途C．望梅止渴D．膝跳反射