6. The best placement for the underlined phrase would be:
Your Answer is
Correct Answer is J
Explanation
stretching for 1000 miles "extending 1000 miles". According to the meaning of the sentence "Adventurers reach Polar Plateau, a high and cold desert stretching for 1000 miles", so the underlined part should be placed after desert, item J is correct.
Item F: Put it in place to make a sentence adverbial, but it cannot be connected with a high, frozen desert, error.
Item G: by December 1 is an adverbial of time, which cannot be disassembled, wrong.
Item H: modify this noun after adventurers, the meaning does not match.