题目

The city of Venice，in  Italy，is one of a kind．It is built on more than 120 islands，just off arrival．After explaining where my new house was，I told him that I had left the key under the doormat．Since I knew it would be quite late before I could get back，I suggested that be make himself at home and help himself to anything that was kept in the refrigerator（冰箱）．Two hours later my friend phoned me from the house．At the moment，he said，he was listening to some of my records after having had a nice meal．He had found the pan and meat in the refrigerator．Now，he wa已知|a+2|=0，则a = ______.