连词
21.（2014江苏） Lessons can be learned to face the future, ________ history cannot be changed.
A. though B. as C. since D. unless
【答案】A
30.(2012江苏)__________ One's life has value one brings value to the life of others.
A. so that B. no matter how C. as long as D. except that
30. 【考点】连词
【答案】C
【解析】as long as意为“只要”；so that意为“以便；因此”；no matter how意为“不管怎样”；except that意为“除了”。句意为：只要一个人给别人的生活带来价值，那么他的生命就有价值。，根据题意，应选C项。
【难度】一般
