L_lianxi = [    ['Apple', 'Google', 'Microsoft'],    ['Java', 'Python', 'Ruby', 'PHP'],    ['Adam', 'Bart', 'Lisa']]print("打印apple", L_lianxi[0][0])print("打印python", L_lianxi[1][1])print("打印lisa", L_lianxi[2][2])L_lianxi.append("Tom")print("追加练习", L_lianxi)L_lianxi.insert(0, ["Mi", ["HuaWei"], ["Vivo"]])print("指定位置插入练习", L_lianxi)print("删除指定位置联系", L_lianxi)