Unit 10I’ve had this bike for three years.How long have you had that bike over there?I've had it for three years.How long has his son owned the train and railway set?He’s owned it since his fourth birthday.Have you ever played football?Yes, I did when I was little, but I haven't played for a while now.Grammar FocusGrammar Focusfor 和 since 在现在完成时中的应用for 与 since 都能与现在完成时连用，但区别较大：（ 1 ） for 后须接“时间段” He has studied English for five years. 他学英语 5 年了。（ 2 ） since 后须接“时间点” He has studied English since 1999. 他从 1999 年开始学英语。（ 3 ）二者可以转换 for + 一段时间 = since + 一段时间 + ago He has been here for five weeks.= He has been here since five weeks ago. 他到这儿已经有五个星期了。如：He has taught here since he came to China.自从他来到中国就在这儿教书。We have been friends since we met in school.我们从在学校见面起就成为了好朋友。(4) since 能引导时间状语从句 ( 主句用现在完成时，从句用一般过去时 ) ，而 for 则不能。（ 5 ）现在完成时常用句型：①It is (has been) + 时间段 + since + 时间状语或从句It is four days since last Friday.从上周五到现在已经四天了。It has been two years since Jim came to Beijing.吉姆来北京已经两年了。②This is the first (second…) time that + 从句 句型中的 that 从句通常使用现在完成时。如：This is the first time that Jenny and Danny have been to China.这是珍妮和丹妮第一次来屮国。This is the third time that I have seen Karen.这是我第三次见到 Karen 。（ 6 ）均须与延续性动词连用，也可以与非延 续性动词的否定式连用。如 :I have bought this computer since four years ago. (×)I have had this computer since four years ago. (√)I haven’t bought anything for two months.(√ )I haven't heard from him for 3 weeks. (√)非延续性动词和延续性动词的转换leave — be away borr...
