Revision: translate the following sentences
美国警方现已加紧对一名15岁男孩的搜索。 People in America have stepped up their search for a fifteen-year-old boy. 自从上周五晚我就没有看到贾斯汀了。 I have not seen Justin since last Friday night. 该事件引起了公众的极大兴趣... This incident has received great interest...
Present perfect tense