题目

定义☆运算观察下列运算：（+3）☆（+15）＝+18（﹣14）☆（﹣7）＝+21，（﹣2）☆（+14）＝﹣16（+15）☆（﹣8）＝﹣23，0☆（﹣15）＝+15（+13）☆0＝+13．（1）请你认真思考上述运算，归纳☆运算的法则：两数进行☆运算时，同号_____，异号______．特别地，0和任何数进行☆运算，或任何数和0进行☆运算，______．（2）计算：（+11）☆[0☆（﹣12）]＝_____．（3）若2×（2☆a）﹣1＝3a，求a的值．用方框中所给词语的适当形式填空，使文章通顺、完整。like, feed, spend, swim, but, restaurant, scared, kind, take, getIt was sunny last Saturday. Mr. Smith 【1】his children to the park. When they 【2】there, they saw many people. The children went to the lake first. There they saw many fish 【3】in it. Jane said, “Look! They are so happy. I hope I can swim 【4】 them. ” Then they went to the bird garden. There were different 【5】of birds in it. These birds were not 【6】when people got close to them. Mr. Smith bought some bird food for the children 【7】 them. The children were very happy. After【8】 many hours in the park, the children were hungry (饥饿的). Then Mr. Smith took them to a 【9】for lunch. The food was expensive 【10】very delicious. All in all, they had a great day.