分类：教育/科学-外语学习-英语考试
问题：新概念英语：句子是否有误1.Hundredsofstepslea 
1.Hundrs of steps lead to the high wall which surrounds the president's palace2.However, he had at last been allowed to send a fax in which he informed the editor that he had been arrested while counting the 1,084 steps leading to the fifteen-foot wall which surrounded t1.Hundrs of steps lead to the high wall which surrounds the president's palace2.However, he had at last been allowed to send a fax in which he informed the editor that he had been arrested while counting the 1,084 steps leading to the fifteen-foot wall which surrounded the president's palace.我认为以上两句中的surrounds 和surrounded 均应该改为surround，请问正确吗？
回答："Surrounds" is correct because the subject of this verb is "the high wall," which is singular and requires a singular verb.  "Surrounded" is correct because the sentence is in the past tense.  In addition, subject of this verb is "the fifteen-foot wall," which is also singular; so even if the sentence were in the present tense, "surround" would be incorrect because it is a plural verb.