straighten sth
He straightened his tie.
他弄正了领带。
弄直；使变直；变直
straightens — third person singular of straighten
整理；收拾；理顺；挺直身子；站直；澄清；弄清楚；使变直；弄直。；变直；挺直。
to make something straight, or to become straight
及物意为“把…弄直”，不及物意为“变直”
使变直；弄直。
To cause to become straight.
变直；挺直。
To become straight.
整理；整顿；收拾整齐。
To put in order; to sort; to tidy up.
向听众阐明；解释清楚。
To clarify a situation or concept to (an audience).
(尤指从坐姿)站直；挺起身来。
To stand up, especially from a sitting position.
一般现在时
She straightens her hair every morning.
她每天早上都把头发弄直。
一般过去时
He straightened the picture on the wall.
他把墙上的画弄直了。
现在进行时
They are straightening the room now.
他们正在整理房间。
动词变位规则：规则动词
She straightened the picture on the wall before leaving.
她离开前把墙上的画扶正了。
用法提示：straighten 作及物动词，意为“把……弄直”，这里接宾语 the picture。
He straightened his tie and walked into the interview room.
他整理了一下领带，然后走进面试房间。
用法提示：straighten 此处为及物动词，表示“弄直、整理”，宾语是 his tie。
Please straighten your back and look forward during the exercise.
做这个动作时，请挺直背部，目视前方。
用法提示：straighten 为及物动词，意为“使……挺直”，这里接 your back。
He straightened his tie.
他弄正了领带。
可指整理物品或直起身子
Please straighten up your room before guests arrive.
请在客人到来前整理好你的房间。
We need to straighten out this misunderstanding.
我们需要澄清这个误会。
反身用法
She straightened herself in front of the mirror.
她在镜子前挺直了身体。
侧重将物品摆放整齐，常用于房间或桌面，较口语化
语气稍正式，强调使外观整洁，但不似tidy常用
侧重于按一定顺序或布局放置物品，不强调整洁程度
grammar · medium
易错句子I have straighten my hair.
正确表达I have straightened my hair.
中文学习者容易忽略动词过去分词形式的变化，在完成时中应使用过去分词straightened，而不是原形straighten。
grammar · medium
易错句子He straighten his tie.
正确表达He straightens his tie.
一般现在时第三人称单数主语he后，动词需要加-s，straighten应变为straightens。中文没有此类变化，因此常被遗漏。
straight是形容词或副词，表示‘直的’或‘直接地’，不能作动词；straighten是动词‘弄直’。
stretch强调拉长或扩展长度/宽度，而straighten强调使弯曲的东西变直。
tighten是使变得紧密或牢固，与straighten的方向相反（收紧 vs 弄直），但发音相近。
整理；直起身来
Please straighten up your room before you leave.
离开前请整理好你的房间。
解决；澄清
We need to straighten out this misunderstanding.
我们需要澄清这个误会。
拉直头发
She decided to straighten her hair for the party.
她决定为派对把头发拉直。
straight (直的) + -en (使成为)
解决；澄清；整顿
We need to straighten out these misunderstandings before the meeting.
我们需要在会议前澄清这些误会。
整理；直起身来
Straighten up your room before guests arrive.
在客人到来之前整理好你的房间。
纠正某人；让某人改邪归正
His friends tried to straighten him out after he started skipping school.
他逃学后，朋友们试图纠正他。
打起精神，好好表现
I need to straighten up and fly right if I want to keep this job.
如果我想保住这份工作，就需要打起精神，好好表现。
Dictionary facts from ECDICT, WIKTIONARY.