Questions

Could is used in hypothetical situation, where we want to express ability except willingness. So, ‘could’ should be replaced with should.

Since, the sentence starts talking about the ultimate hope; it should be followed by the statement that is talking about the hope. So, only statement Q connects with the given statement. Also, in the options there is a single option with starting statement as Q. The correct formation would be, ‘The ultimate hope that the destructive nature of weapons will force the nations to give up war has not been fulfilled.’

Since, the sentence starts with a subject, the next statement will carry a relative pronoun connecting the statements. S follows the opening statement. P will be the next statement which is mentioning the other feature of the man. Q will be the next statement as it describes another quality of man. Thus, R will be the concluding statement and thus form a coherent paragraph.

The correct formation would be, ‘The man who can play most heartily when he has the chance of playing is generally the one who can work very hard when he must work’.