题目

Hello! My name is Tom. I like to go out for a picnic with my father and mother on Sundays. I like fish and vegetables very much. My father is a driver. He likes meat and fish a little. My mother is an office worker. She likes apples and vegetables very much. But she doesn’t like bread and hamburgers at all. So we usually take some fish, meat, vegetables and apples with us. Then my father gets water. My mother likes to cook for us and she cooks fish, meat and vegetables. I fly a kite. We sing some songs. We are all very happy.【1】Tom likes to ______ with his parents.A.go shopping B.go out 已知e1，e2是夹角为π的两个单位向量，a＝e1－2e2，b＝ke1＋e2，若a·b＝0，则k的值为________．