A:should
B:would
C:should have
D:must have
“人”加一笔变成____。
-- John, is Henry your twin brother?
-- Oh, yes. He is twenty minutes ____ (old) than me.
①真理具有反复性和无限性
②人能够能动地认识世界
③真理是理论与实践的统一
④自然界的规律是客观的