题目

The teacher said, The sun rises in the east and goes down in the west. →The teacher said that the sun ______ in the east and ______ down in the west. A . rise; goes B . rising; going C . to rise; to goes D . rose; went 答案：A（10分）如图，在平面直角坐标系中，菱形OBCD的边OB在x轴上，反比例函数（x＞0）的图象经过菱形对角线的交点A，且与边BC交于点F，点A的坐标为（4，2）．（1）求反比例函数的表达式；（2）求点F的坐标．