though 是从属连词,可以引导复合句, 即让步状语从句,例如:
Tough it was late, we decided to set out. 虽然已经晚了, 我们还是决定动身了。
I will try it, though I may fail. 使我可能失败, 我也要试一下。
and 和but是并列连词,只能连接并列句,例如:
I did not answer, and he, too, kept silent. 我没有回答, 而他也不作声。
Nearly everybody enters for‘The Nicest Garden Competition’each year, but Joe wins every time. 年年几乎大家都报名参加“最佳花园竞赛”,但每次获胜的都是乔。