比9156少869的数是____

已知$f\left(x\right)=\left\{\begin{array}{c}x-5\left(x\ge 6\right)\\ f\left(x+2\right)\left(x<6\right)\end{array}\right.$，则f(3)为（   ）

如图表示光照强度对阳生植物和阴生植物CO₂吸收量的影响．下列说法错误的是（　　）

    Many people like animals．Now a lot of people keep animals as pets(宠物)．Usually people like to keep dogs，cats，fish and other animals．Many young people keep animals because they think these animals are interesting．Some old people keep pets because they don’t live with their children．

    Martin lives in No．25 Garden Street．He is a doctor(医生)，but he helps dogs．People usually call him The Dog Doctor．When their dogs get sick(生病)，they call him on the telephone．He goes to the people’s houses and helps them．He gives the dogs the right medicine(药物)．Wherever(无论)he goes，he is always welcome．

如图所示的杠杆，每个砝码重均为1牛顿，杠杆处于平衡状态，若在杠杆两边各减去一个砝码，则（　　）