题目

American and British people both speak English of course. But sometimes there are some important differences between British English and American English. First of all, they sound very different. Often, Americans don't say each word separately. They say words together. Americans may say I dunno instead of I don't know. Or they may say Whaddya say? instead of What did you say? However, the British are more careful. They usually say all the words and keep them separate. Sound is not only the difference. Words sometimes have different meanings too. For example, the vocabulary for cars and driving如图所示，光滑绝缘水平面上带异号电荷的小球A、B，它们一起在水平向右的匀强电场中向右做匀加速运动，且保持相对静止．设小球A的带电量大小为QA，小球B的带电量大小为QB，下列判断正确的是（ ）A．小球A带正电，小球B带负电，且QA＞QBB．小球A带正电，小球B带负电，且QA＜QBC．小球A带负电，小球B带正电，且QA＞QBD．小球A带负电，小球B带正电，且QA＜QB