在横线上填入正确的颜色单词。

                                                       What color are their l. _____?

      Kate, Jim, Rose and Bill put their sweaters on the table. The sweaters are white, blue, red and

black. We know, the boys' sweaters aren't red and the girls' sweaters aren't black. What color is

Kate's sweater? I don't know. But I know Kate doesn't like blue. Bill says, "My sweater is white. "

Then what color are their sweaters?

2. Kate's sweater is _____.                      

3. Rose's sweater is_____.

4. Jim's sweater is _____.                  

5. Bill's sweater is_____.

如图所示，质量为m带电量为-q的微粒（重力不计），在匀强电场中的A点时速度为v，方向与电场线垂直，在B点时速度大小为2v，已知A、B两点间距离为d，求：

①A、B两点间电压？

②电场强度大小和方向？