1960年11月，中央发出了《关于农村人民公社当前政策问题的紧急指示信》，信中强调要坚决反对和彻底纠正“一平二调”的错误，允许社员经营少量的自留地和家庭副业，放手发动群众整风整社等。这表明（    ）

一种声波从水里传到空气中，它的传播速度将（   ）

   The future can be difficult. There are many famous predictions 1 never came true.Before 1929, there was no sound in movies. The head of one of the2movie companies in the United States predicted that no one would want to see actors 3. Of couse,he was wrong! In 1979,the head of the largest computer company in the United States said,“No one will want to have a computer in his or her home.” He thought that computer would never 4by most people.