题目

函数的定义域为___________. 答案：【答案】【解析】根据分式分母不为零、偶次根式被开方数大于等于零和对数真数大于零可构造不等式求得结果.由题意得：，解得：的定义域为：故答案为：Kate's dad is getting old. She will go back home to see him _____it is convenient. A．because          B．whenever         C．although          D．unless