S1: The dictionary is the best friend of you task. P : That may not be possible always. Q : It is wise to look it up immediately. R : Then it must be firmly written on the memory and traced at the first opportunity. S : Never allow a strange word to pass unchallenged. S6: soon you will realize that this is an exciting task. The Proper sequence should be: A. PQRS B. SPQR C. QRPS D. SQPR

The correct answer is D. SQPR.

Here is a brief explanation of each option:

• Option A: PQRS is not the correct sequence because it does not follow the logical flow of the text. The first sentence states that the dictionary is the best friend of your task. The second sentence states that it is wise to look up a strange word immediately. The third sentence states that the word must be firmly written on the memory and traced at the first opportunity. The fourth sentence states that never allowing a strange word to pass unchallenged is an exciting task. This sequence does not make sense because the third sentence should come after the second sentence.
• Option B: SPQR is not the correct sequence because it does not follow the logical flow of the text. The first sentence states that the dictionary is the best friend of your task. The second sentence states that it is wise to look up a strange word immediately. The third sentence states that never allowing a strange word to pass unchallenged is an exciting task. The fourth sentence states that the word must be firmly written on the memory and traced at the first opportunity. This sequence does not make sense because the third sentence should come after the second sentence.
• Option C: QRPS is not the correct sequence because it does not follow the logical flow of the text. The first sentence states that the dictionary is the best friend of your task. The second sentence states that never allowing a strange word to pass unchallenged is an exciting task. The third sentence states that the word must be firmly written on the memory and traced at the first opportunity. The fourth sentence states that it is wise to look up a strange word immediately. This sequence does not make sense because the third sentence should come after the second sentence.
• Option D: SQPR is the correct sequence because it follows the logical flow of the text. The first sentence states that the dictionary is the best friend of your task. The second sentence states that it is wise to look up a strange word immediately. The third sentence states that the word must be firmly written on the memory and traced at the first opportunity. The fourth sentence states that never allowing a strange word to pass unchallenged is an exciting task. This sequence makes sense because the third sentence comes after the second sentence.