S1:American idealism is essentially a  belief in the idea of progress

S6:This sense may have inherited from the English

P:Therefore,he believes that,because of human effort,the future will be better than the past

Q:But,if Americans are usually optimistic,they are not wholly unrealistic

R:The Americans tends to view history as a record of human achievement

S:They have a common sense practicality

The proper sequence is

S1:The machines that drive modern civilization derive their power from coal and oil

S6:Nuclear energy may laso be effectively used for this purpose

P:But they are not inexhaustible

Q:These sources may not be exhausted very soon

R:A time may come when some other sources have to be tapped and utilized.

S:Power,of course,may be ontained in the future from forests,water,wind and withered vegetables

The correct sequence is

S1:Mr Sherlock Holmes and Dr Watson were spending a weekend in a University town

S6:It was clear that something very unusual happened

P:One evening,they received a visit from an acquaintance,Mr Hilton Soames

Q:On that occasion,he was in a state of great agitation

R:They were staying in furnished rooms,more than necessary

S:Mr Soames was a tall thin man of a nervous,excitable nature

The proper sequence should be

S1:Hope springs eternally in the hearts of men

S6:This is the central idea of the poem

P:But hope is everlasting

Q:Love,friendship and youth perish.

R:It is nursed by glorious elements of nature

S:Man derives hope from nature in his gallant struggle  after some noble ideal.

The proper sequence should be

No one would explain how a calm and stable person like him would penetrate such a mindless act on friends

I would have waited for you at the station if I knew that you would come