A number of children ________ parents had died in the quake were sent to live with families in other cities.

导致桦尺蠖体色变化的动力原因是                    　（　　　　）

已知函数f(x),g(x)是定义在R上可导函数，满足f'(x)g(x)-f(x)g'(x)<0，且f(x)>0,g(x)>0，对$a\le c\le b$时。下列式子正确的是（   ）

科技人员用高产倒伏小麦和低产抗倒伏小麦培育出高产抗倒伏小麦，这说明（  ）

   The girl is my friend. She is thirteen 1 old. She is 2 with long legs. She 3 long hair, but she has a 4 face like an apple. She has two big black eyes and small ears. 5 mouth is big, but her nose is6. She likes red, but now she is 7a yellow skirt and brown 8. She is a nice girl. She and I9 good friends. 10 is she? She is Linda.