Complete the sentences using the right preposition. 1. we got the train in london. 2. it turned that all the liked that idea. 3. please don't rush without knocing. 4. the clock had run . 5. he sent writing a letter to his son. 6. i'll do the living room. ​

The rapid development of technologies makes the diverse educational mode come true. an increasing number of universities have opened up distance education in many countries at present. at the same time, hundreds of millions of people will benefit from the emergence of brand-new educational mode. from my perspective, i stand on the side of the view that the positive development from distance learning outweighs its negative effect.there is a common recognition that high quality of education should be available for all to enjoy, not just confined to the rich students. take studying abroad as an example, before appearing distance learning, poor students have no chance to take part in further education abroad because of shortage of money. however, now these students can gain the same quality knowledge by spending less tuition. in addition, distance learning is not restricted to special targets and places. the schedule of distance learning is flexibility so that workers can have classes on their leisure time, which cannot affect workers’ daily work, more important thing is both students and workers can choose study places wherever they want. furthermore, schools will save plenty of expenditure on classroom to improve teacher quality.however, there are certainly shortcomings on distance learning. to begin with, taking traditional classes, we can acquire a variety of opinion on group discussion while distance learning is considerably hard to carry out discussion classes with other overseas students. in the second place, distance learning is unable to use without internet. if we suffer from enormous disaster like earthquake or tornado that makes our internet break off, our learning had to halt until the internet recover.in conclusion  , as a  coin has two sides, distance learning without exception. distance learning is not only to make universal education possible but also to promote international exchanges.

1. The father has already cleaned his car.
Has the father already cleaned his car?
The father hasn`t already cleaned his car.

2. The train has just arrived.
Has the train just arrived?
The train hasn`t just arrived.

3. She will have finished her report by tomorrow morning.
Will she have finished her report by tomorrow morning?
She won`t have finished her report by tomorrow morning.

4. The firm had made good profit by the end of the year.
Had the firm made good profit by the end of the year?
The firm hadn`t made good profit by the end of the year.

5. Our salaries have increased twice since last year. 
Have our salaries increased twice since last year?
Our salaries haven`t increased twice since last year.