層層關卡，困難重重
Taiwan’s constitution has undergone the amendment process seven times since 1991.
自1991年以來，台灣的憲法已經歷了七次修正。
undergo(v.)經歷、經受、遭受undergo-underwent-undergoneamendment(n.)修正、修正案、改進
In each of these instances, constitutional changes were approved by the National Assembly, which was the most powerful legislative body in the Republic of China at the time.
每一次的修憲都是由當時中華民國最具權力的立法機構——國民大會所批准。
instance(n.)例子constitutional(adj.)憲法的approve(v.)批准;通過the National Assembly國民大會body(n.)機構
However, it was during the last round of revisions in 2005 (which was also the last year that the National Assembly existed) that the rules for amending the constitution were changed.
然而，在2005年最後一次修憲時（也是國民大會存在的最後一年），修憲的規則也隨之改變。
it was...that...強調句;分裂句round(n.)一輪、一回合、一局revise(v.)修正、修改revision(n.)修正=modification
In this final revision made on June 7, 2005, the current process for amending the constitution is spelled out.
在2005年6月7日的最後一次修憲中，明確規定了現行的憲法修正程序。
spell out解釋清楚、詳細說明
In order to start the amendment process, one-fourth of the Legislative Yuan’s members must agree to the initial proposal of a constitutional change.
要啟動修憲程序，立法院必須有四分之一的立委同意修憲的提案。
in order to VR為了=with a view to V-ingin the initial stage在最初階段
It must then be “passed by at least three-fourths of the members present at a meeting attended by at least three-fourths of the total members of the Legislative Yuan.”
然後，必須「在立法院至少四分之三立委出席的會議上，獲得至少四分之三的出席委員同意，才能通過提案。」
present(adj.)出席的absent(adj.)缺席的
Six months after this occurs, Taiwan’s citizens become involved in the process.
六個月後，台灣公民將參與這一過程。
involved in...參與～
This is when any proposed constitutional changes are put to a public vote through a referendum, in which the country’s electorate casts ballots to decide if they agree or disagree with the constitution being amended.
此時，任何修憲提案都將通過公投的方式交由全國選民投票決定。
referendum(n.)公民electorate(n.)(全體)選民cast a ballot投票=cast a vote
If an “absolute majority of eligible voters” votes in favor of the change, then it will be considered approved and the amendment will be made.
如果「絕對多數的合格選民」贊成該修憲，那麼修正案將被視為通過，並正式修憲。
an absolute majority of…絕對多數的～eligible(adj.)合格的vote in favor of...投票支持～vote against...投票反對～be considered (to be)...被視為～
Despite this process existing, many believe that the multiple steps involved make it nearly impossible for Taiwan’s constitution to be amended.
儘管有這個程序存在，但許多人認為，由於涉及多重步驟，修憲幾乎不可能。
despite(prep.)儘管=in spite ofmultiple(adj.)多重的nearly(adv.)幾乎=almost
In fact, ConstitutionNet writer Su Yen-tu notes that the country has “one of the most difficult constitutional amendment processes in the world,” and it is because of this that no amendments have been made since 2005.
事實上，《憲法網》作者蘇彥圖指出，台灣擁有「世界上最難修憲的程序之一」，正因為如此，台灣自2005年以來就沒有進行過修憲。
it is...that...強調句;分裂句