题目

阅读短文，从每题所给的A、B、C和D项中，选出最佳选项。 The evidence for harmony may not be obvious in some families. But it seems that four out of five young people now get on with their parents, which is the opposite of the popularly-held image （形象）of unhappy teenagers locked in their room after endless family quarrels. An important new study into teenage attitudes surprisingly shows that their family life is more harmonious than it has ever been in the past. “We were surprised by just how positive today’s young people seem to be about their families,” said（11·钦州）（本题满分6分） 如图，E、F是平行四边形ABCD对角线AC上的两点，BE∥DF．求证：BE＝DF．