В кратце: Артикль a и an означает one (один, 1 штука чего-либо). a используют для слов, начинающихся с согласной (a banana), an для слов, начинающихся с гласной (an apple). Употребляют для не определённых слов, когда речь идёт просто о каких-то там яблоках или бананах (куртке, человеке итд) The означает этот, какой-то определённый предмет, о котором идёт речь, о котором вы уже разговариваете (the book - ЭТА книга), а так же употребляется для небесных тел, как солнце (the sun), луна (the moon), для названий фильмов (the Simpsons), когда вы говорите о солнце, все ведь понимают о каком солнце речь, это же не огурец или заяц.
1) Researchers have admitted that they do not really know how much global warming will increase in the next fifty years. 2) My professor congratulated me on passing with an A. 3) Tom asked me if I had stayed at home or gone out the day before. 4) At that time the exterior of the hotel was still being renovated. 5) They offered to do their best to situation. 6) At the car rental desk, they told them not to leave theirr luggage in a rental car. 7) Their brother apologised for not having been able to provide much support lately. 8) Visa application forms are required to be filled in online.
2) My professor congratulated me on passing with an A.
3) Tom asked me if I had stayed at home or gone out the day before.
4) At that time the exterior of the hotel was still being renovated.
5) They offered to do their best to situation.
6) At the car rental desk, they told them not to leave theirr luggage in a rental car.
7) Their brother apologised for not having been able to provide much support lately.
8) Visa application forms are required to be filled in online.