题干
Pip ______ a gentleman and ______ Estella’s love, who is a beautiful girl.
A：is bent to becoming; winning
B：is bent on becoming; wi
C：is determined to become; winning
D：is determined to become; wi
答案(点此获取答案解析）
D
，当电流从“+”极流入时二极管能通电且发光，当电流从“﹣”极流入时二极管不能发光，则该变光二极管的内部结构可能是下图中的（ ）