Unit 1 Tales of the unexplained Period 5 Grammar and Usage Present perfect tense & present perfect continuous tenseTeaching aims:1. Help Ss learn how to form and use the present perfect tense2. Help Ss learn how to form and use the present perfect continuous tenseTeaching methods:1. Reading2. Practice Teaching procedures:Step one: Lead-in 1. Make Ss to look at the following sentences and point out what tense or tenses are used in them and the reason why they are used.1) We have studied English for about five years. We began to study it five years ago.2) They moved to the south in 1990 and have lived there since then.3) The student is doing her homework. She hasnt finished it yet.4) Eric left home last year and has just come back.Take sentence one as an example:The time we began to study English was at a definite time in the past, so we use the past simple tense. But the action study happens again and again, so we use the present perfect tense.Tell Ss: When an action happens over a period of time that began in the past and continues to the present, the present perfect tense is often used.Step two: Reading Ask Ss to read point 16 on page 8 and explain the reasons why they are used in these sentences.Then ask Ss to read point 13 on page 9.Tell Ss that we use present perfect continuous tense to talk about actions that started in the past and are still continuing, or have just finished but are still connected to the present in some way. Examples: Ive been waiting for an hour and he still hasnt turned up. Im so sorry I am late. Have you been waiting long?Step three: Difference between Present perfect or present perfect continuous Ask Ss to read point 1-4 on page 10 and know the difference between them.Step four: Practicea) Ask Ss to finish doing part A & B on page 11.b) Ask Ss to finish Part C on page 88.