The first “match” for the selection of candidates from dthe Democratic and rRepublican parties for the U.S. presidential election was held in De Moines, Iowa, on the evening of the 3rd of February. Four candidates (fought against each other (?)contested the primary, including Bernie Sanders（age: 78) from the left-wing partyfaction, and a former vice president, Joe Biden (age: 77) from the non-radical partymoderate faction. Due to the delay in vote counting operation,, the caucus began in a great upheaval. ¶
The result hasn’t been disclosed as of midnight of the 4th of February, Japan time. ¶
Based on the entrance survey of the caucus, the New York Times reported that candidate Sanders is most likely to win. However, later, the statement was revoked. Sanders emphasized at the caucus saying, “original quote”, and showed his confidence in winning. ¶
At¶
In Iowa’s public opinion surveyolls, Sanders overtook Biden(?) ( and) gained the lead in the average approval rate. He is also leading in the next primary election scheduled in New Hampshire for the 11th of February. ¶
If candidate Sanders wins twice consecutively, … (he will gain more momentum? confidence? approval?) in the race for the nomination (?). ¶
Sanders’ liberal policies including free college education and a large corporate tax increase are gaining great popularity. The background behind this is thea sign (?) of the public, especially the younger generation, expressing (voicing?) their concerns towardsabout widening inequality. ¶
According to the Washington Post’s entrance survey, 48% of the voters aged 17 to 29 are in favor of candidate Sanders. As many as 31% of the electors who are supporting the policy to reduce inequality selected candidate Sanders. ¶
Elizabeth Warren( age: 70) from the same left-wing party(?)faction followed with 26% of the votes. ¶
However, some question the possibility of the left-wing candidates winning the election against Trump. ¶
Liberal policies tend to be avoided among the working-class that supported President Trump in the 2016 election in the mid-western swing states such as Michigan. (How can I make this sentence sound more concise….?)
Candidate Biden claims that he is the most suitable candidate to recapture (regain?) the popularity among the white middle-class. He told his supporters the evening of the 3rd that the day has been a close (match?) and that it is going to be a long night. ¶
According to an entrance survey, Biden gained 25% of the votes from the centrists. ¶
The youngest candidate on this election, Pete Buttigieg (age: 38), a former mayor of South Bend, Indiana, also gained 25% of the votes from the centrists equaling to Biden. His team is confident that they were able to leap out to the top. ¶
At the caucus held on the evening of the 3rd, Buttigieg commented, “original quote” and showed his confidence regarding the result. ¶
The structure of left-wingers and centrists fighting for the top (position?) is similar to that of between the former secretary of state Hilary Clinton and candidate Sanders in the 2016 presidential election. A widely accepted opinion for candidate Clinton’s loss is that at the end of a fierce battle between the two candidates, some of the Sanders’s supporters ended up not voting for candidate Clinton. ¶
The current situation where both parties are clearly divided indicates that the history might repeat itself in the 2020’s election as well.

The first “match” for the selection of candidates from democratic and republican parties for the U.S. presidential election was held in De Moines, Iowa, on the evening of the 3rd of February. Four candidates (fought against each other (?) including Bernie Sanders（ (age: 78) from the left-wing party, and a former vice president, Joe Biden (age: 77) from the non-radical party. Due to the delay in the vote counting operation, the caucus began in a great upheaval. ¶
The result hasn’t been disclosed as of midnight of the 4th of February, Japan time. ¶
Based on the entrance survey of the caucus, the New York Times reported that candidate Sanders is most likely to win. However, later, their statement was revoked. Sanders was emphasizedtic at the caucus, saying, “original quote”, and showed hiseemed confidence int of winning. ¶
At Iowa’s public opinion survey, Sanders overtook Biden(?) ( and) gained the lead in the average approval rate. He is also leading in the next primary election scheduled in New Hampshire for the 11th of February. ¶
If candidate Sanders wins twice consecutively, … (he will gain more momentum? confidence? approval?) for the nomination (?). ¶
Sanders’ liberal policies including free college education and a large corporate tax increase are gaining great popularity. The background behind this is the sign (?)approval of the public, especially the younger generation, expressing (who are voicing?) their concerns towardsgiven the widening inequality in society. ¶
According to the Washington Post’s entrance survey, 48% of the voters aged 17 to 29 are in favor of candidate Sanders. As many as 31% of the electors who are supporting the policy to reduce inequality selected candidateupport Sanders. ¶
Elizabeth Warren( (age: 70) from the same left-wing party(?), also a Democrat, followed with 26% of the votes. ¶
However, some question the possibilitylikelihood of the left-wing candidates winning the election against Trump. ¶
Liberal policies tend to be avoided among the working-class that supported President Trump in the 2016 election in the mid-western swing states such as Michigan. (How can I make this sentence sound more concise….?)
Candidate Biden claims that he is the most suitable candidate to recapture (regain?) the popularity among the white middle-class vote. He told his supporters the evening of the 3rd that the day has been a close (match?)outcome and that it is going to be a long night. ¶
According to an entrance survey, Biden gained 25% of the votes from the centrists. ¶
The youngest candidate on this election, Pete Buttigieg (age: 38), a former mayor of South Bend, Indiana, also gained 25% of the votes from the centrists equaling to Biden. His team is confident that they werould be able to leapcome out to theon top. ¶
At the caucus held on the evening of the 3rd, Buttigieg commented, “original quote” and showed his confidence regarding the result. (You used almost this exact wording above)¶
The structure of left-wings and centrists fighting for the top (position?) is similar to that of between the former secretary of state Hillary Clinton and candidate Sanders in the 2016 presidential election. A widely accepted opinion for candidate Clinton’s loss is that at the end of a fierce battle between the two candidates, some of the Sanders’s supporters ended up not voting for candidate Clinton. ¶
The current situation where both parties are clearly divided indicates that the history might repeat itself in the 2020’s election as well.

Well done, though I would do a reread of your work to see if you have repeated your turns of phrase/word choices, as it feels like it circles back in on itself. As another commenter mentioned, we don't really use "left-wing" or "centrist" so much as liberal, democratic socialist (in the case of Sanders) and moderate. Good work. Chunking out the sentences might help the editing/correction process as well.