Bigfoot_is_one_of_the_world­famous_mysteries.

　　2．它是在北美洲被首次发现的。(被动语态)

　　It_was_first_seen_in_North_America.

　　3．据说它高6～10英尺。(It was said to be ...)

　　It_was_said_to_be_6－10_feet_tall.

　　4．它重达500磅以上。(weigh)

　　It_weighed_over_500_pounds.

　　5．全身覆盖棕色或红色毛，头和眼睛很大。(with短语)

　　It_was_covered_in_brown_or_red_fur_with_large_eyes_and_a_big_head.

　　6．科学家和研究人员已经去那里做调查。(teams of; 不定式作目的状语)

　　Teams_of_scientists_and_researchers_have_gone_there_to_do_research.

　　7．他们已经找到了相关的毛发、粪便(waste)等。(过去分词短语作后置定语； such as)

　　They_have_found_things_related_to_it,_such_as_waste,_fur_and_so_on.

　　8．但是到目前为止，没有其他证据证明其存在。(there be句型； prove)

　　However,_so_far_there_has_been_no_other_evidence_to_prove_its_existence.

　　第四步：句式升级造亮点

　　1．用非限制性定语从句合并句1和句2

　　Bigfoot，which_was_first_seen_in_North_America,_is_one_of_the_world­famous_mysteries.

　　2．用现在分词作定语合并句3、句4和句5

　　It was said to be 6－10 feet tall，weighing over 500 pounds and was covered in brown or red fur with large eyes and a big head.

　　3．用定语从句合并句8和句9

　　Teams_of_scientists_and_researchers_who_have_gone_there_to_do_research_have_found_things_related_to_it,_such_as_waste,_fur_and_so_on.

　　第五步：过渡衔接联成篇

　　Bigfoot,_which_was_first_seen_in_North_America,_is_one_of_the_world­famous_mysteries._

　　Witnesses_described_it_as_an_ape­like_creature._It_was_said_to_be_6－10_feet_tall,_weighing_over_500_pounds_and_was_covered_in_brown_or_red_fur_with_large_eyes_and_a_big_head._Footprints_up_to_24_inches_long_have_been_found.

　　Teams_of_scientists_and_researchers_who_have_gone_there_to_do_research_have_found_things_related_to_it,_such_as_waste,_fur_and_so_on._However,_so_far_there_has_been_no_other_evidence_to_prove_its_existence._Some_people_think_it_may_be_just_folk_tales_or_stories_to_terrify_hikers_and_hunters_in_North_America.