persuade/try to persuade

persuaded sb. to do 或 persuaded sb. that 是“说服 + 成功”的意思，而 tried to persuade 是“试图说服，但不一定成功”的意思。在上面的试题中，the new dress 她已经穿上了，当然“我说服她买它”是说服成功了的。故 tried to persuade 应改为 persuaded(参见 advise $^{2}$ )。 请对比：

1. He persuaded all the world – famous pop stars to come and sing at one of these concerts for free. He also persuaded other people to provide money or to give help. 他说服了所有举世闻名的流行歌星来参加其中的一个演唱会，进行义务演出。他还动员其他的人出钱或者给予帮助。

2. He tried to persuade them to set him free. But they would not listen to him. 他试图说服他们把他放了，但他们不听。