牛津译林英语八年级下册Unit 3 Grammar(共27张PPT)

Unit 3 Online tours Grammar When I was young, my heart was young then, too. We’ve known each other since we were nine or ten. Together we’ve climbed hills and trees. the simple past tense (一般过去时) 一般过去时态表示过去某个时间发生的动作或存在的状态，常和表示过去的时间状语连用； 也表示过去经常或反复发生的动作。 We use the simple past tense to talk about what happened in the past. the present perfect tense (现在完成时) Ⅰ. We use the present perfect tense to talk about an action that started in the past and continues to the present. 表示过去已经开始，持续到现在的动作或状态。 e.g. 1.Daniel has lived in Beijing for two years. 2.Sam has been in the medical team for over a month. the present perfect tense (现在完成时) Ⅱ. We use the present perfect tense to talk about the result of an action. When the action happened is not very important. It may have just happened or happened some time ago. e.g. 1.Daniel has bought a new computer. (Daniel has a new computer now.) 2.Doctor Wang has saved a lot of patients. 表示过去发生或已完成的动作对现在造成的影响和结果。 the present perfect