先通读下面的短文，掌握其大意，然后从A、B、C、D四个选项中选择可以填入空白处的最佳答案。

    Today is Sunday．It's1and warm．My parents，my2and I are all at home.My parents don't have to go to3,and my sister and I don't have to go school.We are all in the yard(院子).Look!My father is4his bike．Hd often goes to work by bike．The bike5takes him about ten minutes．My mother is watering the flowers．The flowers make our yard very6．We all like the flowers．My sister is playing with a dog．It's7pet dog．The dog is very smart．My mother often takes the dog out8a walk after dinner．What am I doing?I'm drawing．I like drawing very much．I want to join the9club at school．

    It's a nice day and we're10in the yard．How happy we are today!

已知 两根之和等于两根之积，则m的值为（    ）

下列关于研究种群数量实验的叙述，正确的是（　　）