야곰’s 「넓고 얕은 지식」

Yesterday morning I got up and looked out of the window. The sun was shining but the ground was very wet. It had been raining. It was not raining when I looked out of the window. the sun was shining. But i had been raining before. That's why the ground was wet. Had been -ing is the past perfect continuous. You can say the something had been happening for a period of time before something else ha..

The past perfect simple is had + past participle (gone/seen/finished etc..). Sometimes we talk about something that happened in the past Sarah arrived at the party This is the starting point of the story. Then, if we want to talk about things that happened before this time, we use the past perfect: When Sarah arrived at the party, Paul had already gone home. Some more example: When we got home l..

Do not use the present perfect (I have done) when you talk about a finished time ( yesterday / ten minutes ago ) The weather was nice yesterday. ( not 'has been nice' ) They arrived tem minutes ago. ( not 'have arrived' ) I ate a lot of sweets when I was a child. ( not 'have eaten' ) Use a past tense to ask When ... ? or What time ... ? When did they arrive? ( not 'have they arrived' ) What time..

The present perfect is a present tense. It always tells us something about now. 'Tom has lost his key' = he doen't have his key now. The past simple tells us only about the past. 'Tom lost his key' = whe don't know whether he has it now or not. We only know that he lost it at some time in the past. Jack grew a beard but but now he has shaved it off. ( so he doesn't have a beard now ) They went o..

Campare When ... ? ( + past simple ) and How long ... ? ( + present perfect ) A : When did it start raining? B : It started raining an hour ago / at 1 o'clock. A : How long has it been raining? B : It's been raining for an hour / since 1 o'clock. We use both for and since to say how long something has been happening. We use for when we say a period of time. (two hours, six weeks etc.) - I've bee..

We use the present pefect to talk about something that began in the past still continues now. Compare the present and present perfect : Amy is in hospital. She has been in hospital since Monday. We know each other very well We have known each other for a long time. I have been doing something (present perfect continuous) = I started doing something in the past and I am still doing it ( or have j..

We are interested in the activity. It does not matter whether something has been finished or not. Ann's clothes are covered in paint. She has been painting the ceiling. Has been painting is the present perfect continuous. We are interested in the result of activity, not in the activity itself. The ceiling was white. Now it is blue. She has painted the ceiling. Has painted is the present perfect ..

We use the present perfect continuous for an activity that has recently stopped or just stopped. You're out of breath. Have you been running? (you're out of breath now) Paul is very tired. He's been working very hard. (he's tired now) We often use the present perfect continuous in this way, especially with how long for... and since... . The activity is still happening or has just stopped. How lo..

자원의 활용이라는 중요한 개념으로부터 시작된 표준해이지만 그것을 개발하면서 알츠슐러는 또 하나의 중요한 개념을 기준으로 7가지 표준해를 정립해 나갔다. 알트슐러는 어떤 기술 시스템들이 수많은 경쟁을 헤치고 살아남아 계속적으로 강한 시스템으로 성장해 가는지에 대해 관심이 많았다. 이런 시스템의 공통점은 무엇일까? 이러한 관점에서 알츠슐러는 18개의 물질장 모델을 포함하는 76가지 표준해를 다음과 같은 5가지 관점으로 분류하여 정립시켰다. Class 1 : 기술적 시스템이 시장에 출현하기 위한 조건들에 관한 것이다. 또한 기술시스템이 출현하면서 내부적으로 발생하는 유해한 작용을 어떻게 제거하느냐에 초점이 맞추어져 있다. Class 2 : 시장에 출현한 시스템이 어떻게 내부적으로 더욱더 강해지고 효율이 향상되..

When we talk about a period of time that continues from the past until now, we use the present perfect (have been / have travelled etc.) Have you ever eaten caviar? (in your life) We've never had a car. Have you read Hamlet? / No, I haven't read any of Shakespeare's plays. In the following examples too the speakers are talking about a period that continues until now (recently / in the last few d..