题目

They arrived at a farmhouse, in front of ________ sat a small boy. 答案：which in front of which还原即in front of the farmhouse。关系代词which指代先行词the farmhouse。在直角坐标系中，以原点O为极点，x轴为正半轴为极轴，建立极坐标系．设曲线C：（α为参数）；直线l：ρ（cosθ+sinθ）=4．（Ⅰ）写出曲线C的普通方程和直线l的直角坐标方程；（Ⅱ）求曲线C上的点到直线l的最大距离．