题目

用两根等长的细线各悬一个小球，并挂于同一点，已知两球质量相等，当它们带上同种电荷时，相距L而平衡，如图所示．若使它们的带电量都减少一半，待它们重新平衡后，两球间距离A．大于L/2     B．等于L/2    C．小于L/2     D．等于L 答案：AC [2015 •黑龙江省佳木斯市第一中学高一下学期期中]The SAT is one of two major tests for the entrance to American colleges and universities. The other test is called the ACT. More than 2 million students take the SAT yearly, including about 100,000 foreign students. The or?ganization of the SAT will change the entrance test in 2016. The College Board announced that the new SAT will no longer test students on rarely used words. But it will include passages from American historical documents or from writings on freedom and human rights.The College Board says words on the new test will be related to usage. Students will be asked to tell the mean?ing of words according to the context of the reading passa?ges. Nigerian student Peace Umoru is in her first year at Howard University. She says the rarely used words are the hardest part for international students. The new test will be easier because of the reform.Eddie West is with the College Board. He says the new test will better predict a student's performance in col?lege. The changes are moving the test in a positive direc?tion. The new SAT pays more attention to skills and abili?ties that students need to succeed. The addition of material about American historical documents could make the test harder for international students. After all, they live in different countries with different cultures. But it's a good chance for them to understand the Declaration of Inde?pendence or Martin Luther King's work, or anything else that might be tested.Students from other countries, particularly those who did not grow up learning English, may feel it is more diffi?cult. For them, the test is in a foreign language. But the College Board says it has formed a free, online educational service. Khan Academy will provide preparation material linked to the newly designed SAT.24.  What will be tested in the new SAT?  A.  All the different meanings of a word.B.  The rare usage of the common words.C.  The difficult words for foreign students.D.  The proper meaning of the words in the passages.25.  The new SAT could be more difficult for international students because _______ .  A.  they are short of skills and abilitiesB.  they often perform badly in collegeC.  they know nothing about American historyD.  they have different cultural backgrounds26.  What's the main idea of the text?  A.  How to prepare for the new SAT.B.  The SAT will change the entrance test in 2016.C.  Advice for foreign .students on passing the SAT.D.  Tests for entrance to American colleges and uni?versities.