已知函数f（x）=$\left\{\begin{array}{c}a{x}^2+2x+1,\left(-2<x\le 0\right)\\ ax-3,\left(x>0\right)\end{array}\right.$有3个零点，则实数a的取值范围是 ____．

下面是张丽同学写的四个化学反应方程式及注明的反应类型，其中对应不正确的是（　　）

如图所示的电路中，电源电压保持不变，闭合开关S，当滑动变阻器滑片向左移动时（）

如图是动、植物细胞的结构示意图，下列说法正确的是（）

Dear Liz,

    Thank you very much ____ your letter and the photos of your ____ (friend) and family. Your parents and friends look really nice ____ the photo. Now I can tell you something about me and ____ (I) family here in New York.

    I've got two brothers. ____ (they) names are Lukas and Andreas and they ____ (be) 16 and 19. My mother is French and her name is Christine. Dad is American and his name's Dieter. Our house ____ (have) got four bedrooms and a small garden. My room is tidy, but my ____ (brother) is not. They don't often clean it. We have a dog, Zak, and we think he's cute. We ____ (love) it a lot.

    Please tell me all about ____ (you) friends and school in your next letter. I'd like to know about English schools.

Love,

Laura