Tham khảo tài liệu 'the grammar of the english verb phrase part 88', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 602 12. Preterite vs present perfect in clauses with temporal adverbials There is however another factor which weighed perhaps more heavily with the Government s decision to introduce some form of control. In the past the Governments of both India and Pakistan voluntarily agreed to maintain strict control over emigration to Britain. LOB In the meantime the peasant derives many benefits from the management of the economy he is to a certain degree cushioned against the natural calamities which made life so difficult in the past. LOB However even if there is a sense of contrast between past and present Br. E. normally uses the present perfect in combination with in the past Whilst the above arrangement together with correct condenser design has been largely used in the past the tendency today is undoubtedly towards the use of adsorption of the impurities from one or more of the process streams. LOB Inclusive pre-present-zone adverbials Inclusive pre-present-zone adverbials can in principle combine with either the past tense or the present perfect the choice of tense depends on the speaker s temporal focus. Inclusive adverbials i. e. prepositional phrases with within or in see can in principle indicate either a past interval or the pre-present zone and can therefore collocate with either the past tense or the present perfect. The choice depends on the speaker s temporal focus see I have spoken I spoke with Tim three times within the last few days. This kind of example is not essentially different from I have spoken I spoke with Tim today see . When did he disappear He disappeared I has disappeared within the last month. In this context the temporal focus is on some indefinite past time in the period leading up to now. Security awareness has increased significantly within the last year. www Two volcanologists by the names of Maurice and Katia Krafft died in a volcanic explosion within the last five years. www Within the last 3 4 decades .
