Aontherappointmentistheslowprogressinabolishing"staggered'boards－－－oneswhereonlyone-thirdofthedirectorsareupforre-electioneachyear,tothreeyearterms.句中为什么用to,（意思是”在其三年任期内”）

Question

Aonther appointment is the slow progress in abolishing "staggered' boards－－－ones where only one-third of the directors are up for re-election each year,to three year terms.句中为什么用to,（意思是”在其三年任期内”）

Answer 1

是up带的这个to
UP TO THREE YEARS
for re-election each year,只是个插入句.
举个简单的例子：
She said,with a knife in her hand,that he was the murderer.
said 后面是that.with a knife in her hand,是个状态插入句.明白了吗?