When the train decelerates evenly, the speed is v when the front end passes the signal light, and the end stops at the signal light, the ratio of the time of the first half train passing the signal light to that of the second half train is () A. 1：1B. 2：1C. （2-1）：1D. （2+1）：1

When the train decelerates evenly, the speed is v when the front end passes the signal light, and the end stops at the signal light, the ratio of the time of the first half train passing the signal light to that of the second half train is () A. 1：1B. 2：1C. （2-1）：1D. （2+1）：1

Using reverse thinking, according to x = 12at2: T = 2xa. Then the time ratio of the second half train and the whole train passing the signal lamp is 1:2, then the time ratio of the second half train and the first half train passing the signal lamp is 1: (2 − 1), so the time ratio of the first half train and the second half train passing the signal lamp is (2-1): 1

How to solve some multiple-choice questions about first-order functions?
I am a student of grade two in junior high school. In the first semester of grade eight, I am weak in one-time function, especially in multiple-choice questions, so I want to find some exercises. Because the unified examination of the whole city will be held on Wednesday, I am in a hurry. I'd better provide more and cover a wide range

A function exercise________________________________________ 1、 (3,4) the coordinates of a point symmetric about X-axis are_________ The coordinates of a point symmetric about the y-axis are__________ The coordinates of the symmetry about the origin are__________ . 2. Point B (- 5, - 2) to X-axis